The Bees of the Eastern United States, Introduction, Mitchell 1960

Foreword This monograph is the culmination of 313proximately 38 years of collecting and research on t h e taxonomy of our native bees Interest in this group was first incited during my employment i n t h e Korth Carolina Department of Agriculture, where one of t h e projects was t h e compilation of t h e list of insect species known to occur in Korth Carolina The list of bee s ~ e c i e saccumulated a t t h a t time (1920) \vis quite small including only about 60 names, and many of these records were obtained from t h e literature rather than from collections made by t h e personnel of t h e Department Initial collections resulted in many additions to this list, but with a considei.;:ble proportion unidentifiable, due either to the inadequate keys then available o r to the Iiumerous apparently undescribed species t h a t were found This presented a challenge ;ind a s a result, this g r o ~ ~ofp insects has become my chief interest and a n expanded lrno\vledge of t h e group a primary objective Beginning with these earlier experience m y associates have influenced my life and professional development Certain of these stand out in memory as having been especially influential, and f o r whatever has been accomplished, some of the cl.edit a t least, belongs to them The head of the Division of Entomology a t t h a t rime ~\.:li Franklin Sherman Aside from t h e regulntory, extension and economic research nctivities then carried O I I by the Dilision, hi\vhere t h e r r search was carried on under the direction of V' M Wheeler and C T C!.lie-; This association with these two out: t n t ~ d i n gteacher\ served to augment my iiitereit and e:1thusiasm f o r taxonomic research U u l i ~ ~this g period one uf the ge::el.L uf bees, l I ~ g u c h i l e ,was selected f o r hpccial :ittention A revision of t h e S o r t h Americ;~ii species was prepared and p n b l i ~ h e d ,nit11 some attention given to t h e species of sc me of t h e other regions of t h e ~ ~ o r l cHo\x;ei l el :ill collecting was general, so f u ,IS t h e bee, a r e concerned, and much n ~ ~ t e r i : , was l ac~ ~ ~ m u l a tw e idt ,h distribution a d host records inclucted While this collcc i irig n as in progress, n bibliogr:~pl~)-w a i belilg conlpiled A photographic method of cop: ing thc literatu~.e, using 33 mm film, xa.: developed before i t came into the general ube it has today During this Linlt , Llno, he).> f o ~ti1111 c i t 1 t ~ficationof the specie.; ,if :tlI I.ee gvenpr.l BEES O F THE EASTERN UNITED STATES, were gradually developed and perfected These have reached a state of completion which suggests the desirability of their publication, even though new records a r e still being made and new species discovered Actual completion of such a comprehensive study as this one is a "will-o'-the-wisp," and there comes a time when i t is best to publish what has been accomplished, in order to make the results available to other workers I t is hoped that publication of these keys and descriptions will facilitate more intensive studies of the taxonomy of bees, a s well as ecological, biological and economic studies of all of the included groups One very important phase of this research has been the study of type collections in the United States, Canada and England I am indebted to many individuals in various institutions f o r assistance in the location of type specimens, for providing facilities for their examination, and f o r freedom of access to the collections Among those that should be named a r e Herbert F Schwarz a t the American Museum of Natural History in New York; I II H Yarrow a t the British Museum (Natural History) in London; G C Varley of the Hope Museum a t Oxford, England; H H Ross, B D Burks and &liltonW Sanderson a t the Illinois Natural History Survey in Urbana, Illinois; E T Cresson, Jr., James A Rehn and H J Grant, J r a t the Academy of Katural Science of Philadelphia; Noel M Comeau a t the Provincial Museum a t Quebec; the late 1Gatha:i Banks, Joseph Bequaert and Wm L Brown, Jr a t t h e Museum of Comparative Zoology a t Harvard University; and C F W Muesebeck, the late Grace Sandhouse, and Ka1.l V Krombein a t the U S National Museula in Washington, D C I am especially indebted to K W MacArthur a t the Public Museum of Milwaukee, Wisconsin, and H G Rodeck a t University of Colorada Museum, for lending several t;pe specimens, and to Harvey B Lovell of the University of Louisville for sending the entire type collection of his father, the late John H Lovell Through the cooperation of Arthur Humes, of the Department of Biology of Boston University, and a t the suggestion of Wm L Brown, Jr., several of the Viereck types of Andrena formerly in the collection of t h e Boston Society of Natural History, that were temporarily lost, have been found and a r e now in the Museum of Comparative Zoology A large amount of undetermined material was received from several of these same institutions a s well a s from a number of others Such collections have been received from Henry Dietrich and Howard E Evans a t Cornell University; T H Hubhell and U K Lanham a t the University of Michig a n ; Roland Fischer a t Michigan State College; J N Knull a t Ohio State Univers i t y ; H E hIiIliron a t the Ulivcrsity of Minnesota; Herbert I i i l f!ight pcr,iclds : i ~ ca p t t o be I)l.ipf :11ir! pea~isuallyi t is sufficie~it to !C:I;-e ! l i c ~ ~i ii i i?:.) !ri.apliic tli.sti.il)iition limited chamber o ~ e rnight i-\ftc.r rel:isi*;g tl~il The av;iil;~!)iliiy of nesting sites, ;11so, is terminal segments of thp abtli*riicir :IL.I> re.moved and placecl in a satur:itci! ~.)l~iticiil;I l i ~ n i t i n gfactor in the c1istrih:rtion of bees, of KOH This is uot he:itecl hut ti!! 1):~rt.: ; i r ~ i ? ,is a co1;seque;Ice such physiogi-aphic a r e left in the cold solutio~if o r 12-2 l:o:~i.s f e n t ~ i r e s21s character of the soil, d e g ~ e eand direction of slope, drainage, ;irno~lnt and Overnight is usually enough This cie.~rst!ic structures suflicierltly without softeniiig or clistribution of rainfall, etc have some bear(listortirig them A f t e r this clearing pl-ocexs ing on t h e occurrence of bees On f:tvorable they a r e separated with dissecting nccclies sites relatively dense populations may build under a microscope and cemented on :I e:i~-c! u p , especially in those groups t h a t :Ire gregarious I t is probably t r u e also t h a t point, on t h e pin with the specimen many species range but a short distance: Detailed collection records a r e giveil olily x nesting ;!Yea Thus there a r e markf o r t h e new species, while the general geo- f ~ o the graphic tiistribution and seasonal c2ccul.- etl vrtriatioris i11 relative nburidance f r o ~ ~ i I.ence a r e given f o r ;ill previui~?,lydesci,ibed one locality t o another, ever1 though the host species T h e flower-visiting habit.: ;i!.;o a r e p l a r ~ t smay he g e n e ~ a l l yavaila1)lt given, a s f a r a s they a r e knux:n Climate of course is impr~rtarlt,limiting T h e list of bibliogi~iphicreferences ~!!~rler ;is i t does the geographic distribution of each genus and species incluites un1y thcjse both t h e hort p l u i ~ t sand t h e bee visitors of some taxonomic, biologic o r ecologic sig- J3ut ~ v i t h i ithe ~ geographic limits of t h i s nificance T h e reference t o t h e original dV2- distribution, the day-to-day o r hour-to-hour scription, is almay:; included, :is :Ire t h e weather corlditions can be very limiting, so veferences to most synonyms AI-ticies far a s a n y success in the collection of many \vhich mri-ely list the species a r e not in- species is concerned Many bees cease activity in the absence o f snnshine, or \trill c.lrided ;t 12 BEES OF THE EASTERNUNITEDSTATES,1 remain inactive cs: iong as the weather i.: logical first abdominal segment is fused with the metathorax and is known as the too cool or windy Time of day is important, for with most 1;,.opode7inz Thus the middle body region species activity is most marked thro1:gh i3:cludes four segments, rather than the the middle four or fire hours of the day To 11-ual three of other insects, and the abdothis, however, there a r e eyceptions as there men conversely includes only the segments a r e a very few species that are nocturnal, 2-5 These terms, however, are limited in their application to t'ne ants, wasps, bees crepuscular or matinal, or time their flight and related insects I t seems better to emto coincide with a bricf periocl early in the ploy ? h e older and mere general!;; used clay when the host flowers are open, as ternlr in a work which i t is hoped n ill have shown by P j ~ r ~ , h o p c r ! : p z ~ sc n r - ~ l i ~ 1 ' ~ ~general 7[~ uyage In numbering the al-dominal (Walt.) DC and its bee visitor, M p ? l ~ i h a - segments also the propodeurn will be dislicfzis l l r s f l n n s Ckll reg:~~-dedas representing the first, but inThus i t can be seen thal to meet with -.car1 the morphological segment 2, will be succew in the c?llecti?n of some of t'ne more ct,n:yid~rect the basal one spcci,?li.;ecl b2es i t is llecessai\- to find a -4 1::teral view of A ~ d , e n u(fig 1) and a combination of conditiolls that inclucies tile Iront -,ri-,::.of the head (fiz 2) show the host p!tinC in bloom, adjacent to or in the gencl-t:l ex-tci-nal charilcteristics Most of near ~ i c i n i t g of some f,~vor:tble nesting the features illustrated are useful in fursite, ~ ~ i t l i ithe n distribution limits of the ~ l i s h i ~speci5c ~g or key characters in one species, during the dai!y active period of or another of the groups of bees, and an flight, and in i ~ a r m c:llm, , sunny weather expl;.,nation of certain of them is desirnble Generalized bees that visit a wide range The fovcaz (fig 2) a r e shallow depressed of hurt plants tend to be in flight f o r much areas on the front of the head and a r e pres!origer periods of time than the specialized ent in the females of the Andrenidae and forms and are u;ually much more widely most of the Colletidae They a r e poorly and generally distributed It is these -forms developed in the males of these two famiwhich are in flight through most of the lies and are lacking in all of the other midsummer period, and i t seems lsossible groups that some of them have more than a single The sz~btctttcnnnl sutzires have some siggencrntion during a seilson The specialized nificalice in classification but a r e m t h e r more restricted species tend to fly either r y key characters as they in the spring or in the fall and probably ~ ~ n s a t i ~ f a c t oas a r e 50 frequently obscured by the dense hat e only a single generation pubescence of the face Only in the And~enic!:\e a r e both the outer and inner pairs Morphology repi-ese~ltecl, the inner pair apparently or absent in all other With reg;ird to general structure, the being much terminology nilopted by Alichcner (11744) groups Because of this they are rarely is followed, although without strict ad- u ~ e din the keys or mentioned in the deherence Some of the terms he has pro- - C riptiqns posed, x:hile certainly logical, a r e different The n ? ~ t e ? z , l u ra~s, in the higher groups of from those usecl for comparable parts in wasps, s1.e 12-s~gmentedin the females and other i~lsectorders, and their use is avoided 13-segmented in the males Usually sexual heye for that reason So f a r a s possible climorphism is so marked in the bees that no ~problein ~ ~ ~ in distinguishing the figures a r e used in place of, instead of as t ! ~ isi ~ supplements to, printed descriptions Only sex?., but where the similarity is col~siderwhere some additional explanation is de- able, as in some of the parasitic groups, sirable is any space devoted to discussion this difference in the number of antenna1 of the parts illustrated segments is helpful The apical ten or The three body regic.2:~ a r e designated eleven segments form the flagellum, and the I ~ m r i ,t1ln1.n.c and abdflnzen, in accord- the relative lengths of these segments, esance u i t h the terininologjr in the orders pecially of the basal one, is of considerable other than the Hymenoptera Michener value as a key character (1944, p 167) uses the terms mesosonza When, as in some groups, the eye is and mefaso??lafor the thorax and abdomen, closely approximate to the base of the mansince in all the Clistogastra the morpho- dible, there is no distinct malar space It INTRODUCTION SECWD S~~~MA,RGINAL CELL I F i S T SUBMARGINAL CELL ; I INTERCURITAL VEINS i ,.' ,MARG~MAL CELL SUBMARGINAL CELL PECL'RSENT VEIV DISCO 5AL CELLS Figure 3Iorpho!ogica! featureh and wing venation o f bees is extenslbe 11-1 lilost of the social bee,, nb \veil as in few other unrelated solita~!: species The lab) u ~ ,nil i ~ ~ i ~ a l ~ d i b er es relatiiely simple ge:leralized structures, not markedl) different from those of more primitilc insects, 1,ut thev show a rather wide range in form and in ] d a t i v e proportions The remaining :ippendages forming the proboscis, the ftzazillae and labizcnt, a r e especially significant in the recognition of the families of bees; hence the importance of having them pulled out into a visible position while the insect is still fresh artd pliable I n the more primitive groups (e.g., Colieiidae) tl1ei.e is a ciose resemblance of thcsc slr~lcttiresto t h x e in the wasps, with :: l.:~.:;adly truncate or bifX glossa, a 4segni+nted labial paIpus and a 6-segmented rilaxiliary palpus (see Colletes, in fig ) 1x1 tile st,ructurally more specialized bees the y1os.x becomes acute aiid more or less elongated, the lacinia becomes reduced in size, the number of segments of the maxi!lary p:.~lpusfs reduced, and various other nlodifications may be found The labium and inaxillae a r e united basally by the Vshaped submentam (lorum) which is attached on each side apically to the tip of the cardo r 17 I nc: posicriol siirf;ice of tile ileiid belc~iv niore priniitii e solitary bees such a s Colis occ~ilpied bj- n deep excavation, the l e f ~ sand Ai/cl,.ciln, in which t h e lateral sur~~i~oi~ri.vc~iclio~ jc,sscr, into n-hich t h e proboscis faces of t h e propotieum have a fringe of fits \\-hen retracted The margin,^ of this elongate 11:iir~ nl;)i~g the upper margin foss:i a r e formed b)- the h!/l)ostoi),ul ccci~itrur~ while t h e cenlra! area of these surfaces is 1I.hic.h a r e quite conspicuous and furnish neariy o r quite devoicl of pubescence Thus tiseful distinctive specific characters in sev- ;r t);isi.:et is fornled into which t h e pollen is esal groups p;icl;etl, and this is knoivn a s the propocleal a more or The thorax is simiial to that of the xphc,- co!.l~icitlrr I n the geliiis 4tlr11.~rln ilelise :ilid pliimose t u f t of elongate less coid ~vasps.with ;I collar-like lit'ouof / I ; , ! , the pohte1,ior ma~.ginof x h i c h is produced nli c~11.vedh;:iis on the hind trochanters is Jlocc~~s eiich side to form :I rounded lith~i~c.!~ The c;i!led t h e i,.vci~cli?fe?~al The wings ( fig ) exhibit a considerable /i~~ol)otlc/oii con~mi~rlly exhibits four distillct surfaces; one dorsal one posterior nrld 1,;irige of val.iation k)et~vcengenera and the t ~ v o 1nter;il I n many species or groups other higher c:itegories but a r e commonly c:f little help ill the separation of species these suifaces a r e clelimited by rn;trgin:il ci~riii;ie,ant1 t h e dorsal surface is further within t h e genus Important clifferences c.tinl~:ictcr.izedby striations, reticulations or inclitde the n ~ i m b o : of submarginal cells other sc~ilpturingwhich a r e of corisitleral~ie I t\\-o or thrcc;), t h e relative size of the stigma the s i z p atid form of t h e marginal t;isoiioniic importance cell, the form of the basal rein and 2nd 'l'hc legs in most fcnlales (differ fronl recurrelit vein ; ~ n d t h e 1-elation of the those of t h e other Hymenoptera chiefly il; i,ecurre~lt veins to the siibmarginal cells t h c i~rondenirigof i h e hind tibiae and hasi- 111 t h e hi11d x i u y the relative size of t h e t;il.si :inti, to some degree, t h e mid basitarsi jug:.al and i-u,!n;il lobes and the relativc ;rIscl i:long TT-itht,he expansion of these lefigths of sc?me of the abscissae of the p ; i r t ~ there has been a developtilent of veins a r e of significance in separating some ~x~llt~l~-coiiecti!~g hairs which a r e borne on of tlie s~iperspecific categories the hind legs in all groups except the Excluding the propodeurn t h c abdomen 3TrgacFiilitine where they a r e fotund o:i the i~iclnclessix n-ell defined segments in the vcwtl.al s ~ t s i a c eof t h e abdomen The basi- fcmale a ~ i dseven in the male Each segt : ~ r s i i;i some groups equal o r cren exceed ment i:: composed of a dol.sal, st]-ongly their tibiae in length so t h a t there a r e ;trc:hed terguni :III(~ ;I l.eliitirel;\ fliit, ventral t h c ~large and conspicuous leg segments s t e r n i ~ m There a r e 110 plei~i~iil plates 111 insteiicl of the usual tn-o (femur and t i b i a ) ma?iy groiips, the Gth tergitin of the female Since males collect no pollen, these leg ;iiici tlie 7th o f (he m;iii liear :L triangular featiires a r c lacking, with all segments 11su- ;:pic:~l plate, t h e ijjj{gi(ii!il p l u i ~ :illy q ~ i i t eslencler and ~vasp-like.Ill paraThe segrilents Iieyo~ltithe 6th ill the fesitic species, moreover both :.eses a r e waspl e 7th in t h r ; ; ~ ~ i lacr e retracted and like in appearance, f o r in these t h e females i l ~ i ~ :i!i;l inuCh rcilit~eit ; ~ n dni,~difiedapparently to 11;ive lost their pollen-collecting orp;lris form a :ic;rtioil of the seproc!uetive strucTTYOfu1.m~ of y3ollell-cullectil1g O I ~ ; L I I S !ur~:: 'ri~itsIY:I:IIXI::Sof t h e '7th and 8th ;ii,e foiilid in bees In ali of o11r 11011-parasitic ~cl.gi!I:i!;ii.es iii't: ;~:::,oci:~!~ti with t h e sting so1itar)- species they :ire composed of locaii r i ti;(: fcnlalc \ii!ilc in the miile t h e reized brushes of hairs, lid the resulii:ig t r:icteii 8!.11 :.ep~iieiii is composed of a terorgan is known a s :I r c o j ~ ~ tL:s~~;ill:~ these g,ruril ::nd sterliuill i~etn-cell ~ v h i c h the scopnl hairs a r e more elongate a:id spine- ::e~iit:li ;irm:iture lit-: 111 sonie groups, such like than t h e other body hairs, ancl the) :i.5 ifr,,qat~iriic', there i:: 2: f'ci rthcr retraction may either be simplt~:end unbranched 01 of some r i f t l ~ eot1lc.l sternal plates This more or les-; clensely plumose The socia! i.es~iItsi l l ;:j> :t!~i~it.:u i a C the abdomen posbees, in the family Apidac, have a more t erior1)-, ::,iilcc?ti1ei.e :ii,e 11!ui)e cxposed terga sli:r.~:l ?'hcse hidden sterna become specializecl strttcturc, callecl the ~ ~ i ' b i ~ / ! lth:ii: a or "pollen-basket." 111 such l e e s t h e oittci ~ : ~ c ~ oi.r cles;: in:irkedIy ~ilnc!ified and consiirface of the hiricl tilii;! is ])arc_nnd h i g h l ~ !.ci\-;a!-t:)- bar.(? 211 sccc3sxr,i,:~-ixproductive 01, : ? S o i ' i ~ c y :Ire significant j)olished :ind is sui-i.c~u~;ded by ;I m:~:.gin:~l i * ~ I'ringe (11' h:iil.s f~1l'rn;ll~ tiie ka:,kt:i rill ~,:.?::i~oi~lc::i~i~~, :ill11 it, i i1CCeSS;LrY sonicJ:.~inlorori.f ' f i l ~ r l l i-: fiil111(1i r i SOITIP ( I f ' It-11, I i r r ~ , ~10 (:-illd in tlic lack of l i , ~ t hthe r~ieiitiirnanti s ~ i h n i e n t ~ i of m the labiuni i t 1.eseml,les the i , l l ~ egenerti ~ i n that f:~mi!:,r 'The chief tiifeive~icesill t h e f r o n t wing? a r e ~vjlll.~ e g ~ t~o rt hde nunibel c;f submargin;~lveils I n 2111 of the 1aIeg;tchiii:lae there ::re olily t\vo subm:irginals t fig dlfylcr~liiic;I , n.Eli!e iri t!ic Xyloccpidae, Apiclae and :~!1 I ) u i o i ~ c:.n~r.ll genus o f I l ~ eAntho!,ho~.ltl,ie tl.1ei.e ;;re: t h i w ! fig Nolcopclsi/iil hairs or1 liropotlt:im, hiild trochantel-s, femora and tibiae Coi!~tes & Alid?,eila Scopal hairs on hind l'exiora & tibize -Cnupolico,~a, I-Ialictidae Scopal hairs 011 \-enter of abdomeli -3legachilidae Scopal hairs oil hind tibiae onlj Panurginae Scopal hairs on hind tibiae :iild biisitarsi-Melittidae A~ithophi;rid:ie Xylocopidae Tibia1 scopa n~udifietl t o f o r m corbicula-Apiclae '7 Scopal hairs I~st-~-H?!(iii:.< & ;ti1 payitsitic Feller2 This ai.raligenic:l~! (it f;t~~ii!ie,q : lid gk:~erii should not be t,ikeli to represeiit ;L phpiogenetic sequence Hylnciis Col1;'i~s and Cu/ipoiicnrin appear to be related to each other eve11 though the:: illustrate different degrees of specializatioa of these pollencarrying organs Parasitic types a r e found in t h e Halietidae, fifepnchilidae, Anthophoridae and Apidae Satisfactory keys to the higher categories of insects, and probablj- of other living organisms also, often a r e di5cult to devise I n a natural classification, the inore significant differences bet~veeizthe more icc111sive groups a r e often obscure o r dificult to observe o r to interpret Furthermore, charwhich we base our acters o r coiiilitioli np~.>n classification often a r e subject to exceptions in some of t h e Ion-er gioiips or species which 5;hould be incl::dcd 111the i ~ e e snros! writers h:ive placed mtich i.e!;lli~::I the condition of i h e mouthparts, iiiic! a relatively simple key to thc i;irizilie-; can i ~ eprepared using these s ? ~ ~ ; , r t i ~ ~ e : ; Unforturi;itely, - i ; ~ ' l;, key is \%isy diiiicclt to use, f o r the mout;:parts usually a r e hidden beneath the lzbrum and ci~:?~edmandibles A specimeg n ~ u l tbc relnxecl, the mandibles spread :ip:xt ai;d the prcboscis pulled out into a visil~lepositioa in oi.cl.er to see them With malerials t h a t have been in a dried condition f o r any leilgti? of time, this often is vei y di:ije~:ll to without damaging t h e speci~neli, a ~ dmRy sometimes prore to be practically impossible Moreover, it is impractical if any large amount of material is involved Also the risk of damage to a unique or type specimen often is too great Thus i t is very desirable to enlploy characters t h a t a r e readily visible, so f a r a s possible, in constructing keys to these larger groups The key below has been pre- pared to t h a t end Wing characters usually a r e clearly visible and a r e significant in the classification of these higher categories Some of t h e difl'erences however, such a s the presence of two or three submarginal cells, a r e subject to some variation within some of the family groups As a result, this key to the families is somewhat longer than HYLAEUS MEGACHILE DUFOUREA - NOMADA OBLITERATA PSEUDOPANURGUS / ANDRENA HEMlHALlCTUS ANDRENOIDES Figure 4-Venation of front wing in representative genera of bees 20 BEES O F THE EASTERNUNITED STATES,1 rrllght be t h o u g h t rletes>;tr>, since t h e s e characters a r e not entirely constant T h e c h a r a c t e r of t h e m o u t h p a r t s i n each g r o u p i s included b u t i s g i v e n a hecvndary or supp o r t i n g position It will b e possible i n m o s t cases t o r u n a specimen t h r o u g h t h e k e y t o t h e p r o p e r f a m i l y w i t h o u t s e e i n g t h e m Included i n t h e k e y i s one andieenid g e n u s , Protc~cr~cr, w h i c h h a s n o t y e t been f o u n d i n t h e e a s t e r n U n i t e d S t a t e s Should i t a p p e a r i n a n y collections m a d e i n t h e e a s t e r n U n i t e d S t a t e s , i t should be possible t o recognize i t i n t h i s key Also, s i n c e m o s t of t h e o t h e r g e n e r a of bees t h a t a r e n o t represerited i n t h e e a s t e r n s t a t e s a r e n o t a s lttypicwl w i t h i n t h e i ~f a m i l i e s a s Protoxaea i n t h e A n d r e n i d a e , i t i s hoped t h a t t h i s key will m a k e i t possible t o r u n a n y n e a r c tic m a t e r i a l s t o t h e p r o p e r f a m i l y K E Y TO FAJIILIES F i o n t wing with basal vein stiongly arched; g!ossa acute, usually short; labrum usually hidden by nlandibles when closed, but if exposed, then much broader t h a n long; pygidial plate poorly developed or absent Halictidae Basal vein very nearly s t r a i g h t ; or if soinemhat arched, then labrum large and fully exposed when mandibles a r e closed ; glossa variable F r c n t ming wit11 no nlore t h a n two submarginal cells F r o n t wing IT-ith three submarginal cells Two submarg~i1:~lcells always present; ~ , ~ a ~ g i ncell a l tranversely o r obliquely t i u ~ l c a t e a t tip; glossa acute, usually short Andrenidae Marginal cell rounded or acute apically, or i f truncate and very short, then but one subma] ginal cell present F i r s t recuiient velri entering f i ~ s t subn ~ a r g ~ r ~tell, a l or *nterstitial with first intercubit, ve:n F i r s t recurlent vein entering second subl l l a r g ~ n a l cell F ~ r s recurrc t n t vein enterlng first submarginal cell ; pygidial plate present; glosqa slender and elongat? Anthophoridae (Scola) , a ) F i r s t recurrent vein interstitial or nearly with first i n t e r c u b ~ t a l vein; pygidial plate absent; glossa short, obtuse; small black bees, usually with yellow face marks Colletidae ( H y l a e u s ) hIalglna1 cell usually lounded apically, but ~f acute, then tip bent away from costa; glossa slender and elongate; fenlales of nonparasitic forms with scopa on venter of abdomen Megachilidae 3larg1nal cell acute or naiiowly rounded apically, only slightly bent away fro111 costa, if a t all; female.: with scopa on him1 pair of legs 7 Antennae in feinale locateci below mid line of face; face in male without yelion ~naculations Halictidae ( D t ~ f o z ~ ~ c u ) Antennae located a t or slightly above mid line of face: clypeus in male yellow h Facial foveae piesent In female; basitibla1 plate well developeti on hind tibia of male : fir.;t s u b n l a ~ginal cell considerably longer than second Andrenidae Facial foreac ahsent: hasitibial plate poorly developed on hind tibia of male; fil-t ant1 second submarginal cells subequal In length Rfel~ttidae(ilfawopis) I (4) ( ) Second recurient veln recurved pos- teriorly toward outel margin of wing or first recurrent vein interstitial with first intercubital vein: glossa short and obtuse or bifid Colletidae no re nearly Second recurrent vein s t r a i g h t ; first recurrent vein entering second submarginal cell, o r interstitial with second intercubital vein; glossa acute 10 X a l a r space distinct, usually extensive; pygidial plate absent; females of nonp a r a s ~ t i cgenera with tibia1 corbicula Apidae 31alal space lacking, or if a t all evident, then pygidial plate well developed; fe~ n a l e sof non parasitic genera with tibla1 ycopa 11 11 C lypeus strongly wnvex, mole o r less encloiirlg the labruxn laterally, this fully eupoqed when mandibles closed and nearly a s long a s broad; pygidial plate usually present 12 Clypeus less strongly convex, the labrum usually partially or entirely covered by the closed mandibles; pygidial plate present or absent 13 12 Basal segment of flagellum equal to the next (female) or (male) combined; glossa relatively short; basal seg~nents of labial palpus short; scopal hairs on 10 NOMADA MELITTA XYLOCOPA Figure 5-Venation of front wing in representative genera of bees hi~lcf coxac,, trochanters, femora and tihiar Xndrenitiae ( P r o t o x u e a ) 1:asal segment of flagellum 110 Inore t h a n equal tu the next co~nbined (usually IIIU-h shortel.) ; glossa slender and elonxate; segments and of labial palpi much elongated; xcopal hairs on hind Anthophoridae tihiae ant1 basitarsi 1': ( 1 ) Facial foveae piesent in felnale; haqitibial plate \vc:l developed on hind Andrenidac tibia of l n a l ~ Facial foveae allsent in female; basitibial plate nut or poorly developed i n inale 14 11 l'ygldial plate well tleveloped; firat submar.pina1 cell about equal to second and thiid combined Slelitticiae ( J I c l i t t u ) I'yyidial plate USL ally abqent, but if a t all evident, then firat submarginal cell 110 longer than the third alone 15 Seconcl submarginal cell more nearly triangulal , with the two intercubital vein5 approxinlatr a i ~ t ~ r i o r l y glossa ; 4entlel and elonqate Xylocopidae Second ~ u h m a r g i n a l cell quadrangular, about as hload a , long, the two intercubital veins neally or quite parallel; ylo->a short and acute Ralictidae (ATo>rriu) Literature Cited Borror, Donald J and Dwight M DeLong, 1954 An Introdz~ction t o t h e S t u d y o f Insects; New York, N Y., Rinehart and Company 11 750-761 Brues, Charles T., A L Melander and Frank M Carpenter, 1954 Classification o f Insects; Harvard Univ., Mus Compar Zool Bul 108, pp 636-659 Cornstock, John Henry, 1940 (9th ed.) Arc Introdz~ction t o Entomology; Ithaca, N Y., Cornstock Publishing Associates, Inc pp 972-990 Linsley, E Gorton, 1958 T h e ecology o f solitary bees Hilgardia 27 ( l y ) , pp 543599 Michener, C D., 1944 Comparative E x t e r nal Morphology, Phylogeny, and a Classification of t h e Bees ( H y m e n o p t e r a ) ; Amer Mus Nat Hist., Bul 82 (6) pp 151-326 Muesebeck, C F W., Karl V Krombein, Henry K Townes, et al., 1951 Hymenoptera o f America N o r t h o f Mexico; Synoptic catalog, U.S.D.A Agr Monog NO 2, pp 1043-1255 Robertson, Charles, 1929 Flozoers and I n sects; Lancaster, Pa., The Science Press Printing Company pp 1-221  ... Through the cooperation of Arthur Humes, of the Department of Biology of Boston University, and a t the suggestion of Wm L Brown, Jr., several of the Viereck types of Andrena formerly in the collection... the separation of the t ~ seems o desirable but the fact that the sphecoid wasps a r e much more closely related to the bees than they a r e to the vespoid wasps or any of the other Hymenoptera... period of or another of the groups of bees, and an flight, and in i ~ a r m c:llm, , sunny weather expl;.,nation of certain of them is desirnble Generalized bees that visit a wide range The fovcaz