: A GENERIC REVISION OF THE FOSSORIAL WASPS OF THE TRIBES STIZINI AND BEMBICINI, WITH NOTES AND DESCRIPTIONS OF NEW SPECIES By John Bernard Parker Professor of Biology, CathoUc University of America INTRODUCTION The wasps comprising the subfamily, Bembicinae, as that sub- family is herein understood, have always been regarded by authori- ties on the Hymenoptera as forming two well-defined groups, the tribes Stizini and Bemhieini of the present paper, but the taxonomic position assigned to the two groups within the family or super- family (Sphecidae or Sphecoidea) by the various authorities has not been uniform. Some, as for example, Ashmead, who, in his scheme of classification, attached great importance to the number of tibial spurs on the second leg, separated these two groups widely; but others, as Cresson, Fox, Kohl, and Rohwer, have considered them closely related and as forming subdivisions of a larger group, al- though these authorities differ from one another as to the rank these subdi;visions should be given. In accepting the subfamily referred to above I am following the classification adopted by J. H. Com- stock in his work, An Introduction to Entomology, published in 1924. The genus Sphecius, which was long included in the tribe, Stizini, does not belong there, as Rohwer has pointed out.^ Consequently that genus is not considered in this revision. In a preceding paper,^ in which I undertook the revision of the BeTTibicini for North America north of Mexico, it was shown that within that region this tribe is represented by the following genera Bemhix Fabricius, Microhemhex Patton, Bicyrtes Latreille {=Be7n- hidxda Burmeister), Steniolia Say, Stictia Illiger, and Stictiella Parker. Wasps included in the last two genera, Stictia and Stictiella, had up to the time of the publication of that paper been included in the genus Monedula as that genus was understood by Handlirsch, • Proc. U. S. Nat. Mus., vol. 50, 1921, p. 403. » Idem, vol. 52, 1917, pp. 1-155. No. 2776.—Proceedings U. S. National Museum, Vol. 75, Art. 5 22764—29 1 1 2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 75 Kohl, and others. In that paper I pointed out, as Fox had done be- fore me, that the generic name Manedula as applied to wasps must be dropped because of its preoccupation in another field, and that its place in Hymenoptera should be filled by the generic term Stictia Illiger. Vespa slgnata Linnaeus was at that time designated as the type of the genus Stictia. I am fully aware of the difficulties that result from the breaking up of an old and long-established genus, such as the genus Monedula^ genera. But when an old genus, as is into a number of new true in i this case, embraces groups of species that possess characters rendering | them just as distinct from one another as these groups are individ- ually distinct from other long-recognized genera in the tribe, there is nothing left to do but to give these gi'oups generic rank if our treatment of the tribe is to be at all consistent. That the genus Monedula,, as undersood by Handlirsch and others, was made up of such groups was pointed out in my previous paper. One of these groups is embraced in the genus Stictia Illiger, typified by Vespa signata Linnaeus, and to a second group the name Stictiella was given with Monedula foronosa Cresson designated as the type. For a third group Burmeister's subgeneric term Hemidula was proposed with Monedula sinffularis Taschenberg as the type of this genus. Among tlie remaining described species not included in the three genera named above, I distinguish four additional groups represented by the following species: Monedula vvZpina Handlirsch, Monedula chilensis Eschscholz. Monedula gravida Handlirsch, and Monedula viagnifica Perty, each of which species is made the type of a new genus. To this list of new genera I have added another based upon a new species described in this paper under the name Selman angv^tus. Inasmuch as I have not seen a specimen of Monedula singulnris i Taschenberg and find myself unable to determine from the available \ descriptions of this species just what generic characters it exhibits, it is possible that one of the new genera proposed herein may prove to be a synonym of Hemidula Burmeister. But from data furnished me by Dr. H. Bischoff, who at my request kindly examined a female of this species in the museum at Berlin, I learn that the mandibles are edentate, a character possessed in this tribe only by members of the genus Mic7'obembex, to which genus Monedula singularis certainly does not belong. The uncertainty attached to the taxonomic position of this species will doubtless remain until representatives of both sexes of the species shall have been obtained. In making this generic revisi(m of the Bemticlni I have studied with some care the various characters that have been regarded as of generic value in this tribe. Of these I have found the make-up of the maxillary and labial palpi of less value than that generally ART. 5 GENERIC REVISION OF THE FGSSORIAL WASPS—PARKER 3 assigned to this feature. My examination of these structures in the several genera was not extensive enough to warrant the drawing of broad conclusions, but it was carried far enough to show that in tlie genus Bembh', in which the typical numbers are four segments for (he maxillary and two for the labial palpus, the variation in the number of segments in the palpi of some species is such as to lessen the value of these structures for generic purposes. Variation in vepect to the number of segments in the palpi was also found in sc»me species of Steniolla and Microhemhex, but the number of individuals examined in each genus was too small to warrant any other state- ment than that variation does occur. In those genera in which the typical number of segments for the maxillar^^ palpus is six and for the labial four, I did not find variation in the limited number of individuals examined. Since these numbers, however, are regarded as indicating primitive conditions, this lack of variation is readily explained. It was this search for variation in the mouth parts that led to the discovery that the number of segments in the palpi of Monedula chUensis Eschscholz is five for the maxillary and three for the labial instead of six and four as had heretofore been supposed. Since in this tribe (Bembieini) the ocelli are much distorted or are reduced to cicatrices. I have found the anterior ocellus providing one of the most reliable characters on which to separate tlie tribe into genera. Although I have found within a genus some A-ariation with regard to the extent to which the reduction or distortion of the anterior ocellus has been carried, I have found no variation in the form which that reduction shows or to w'hich the reduction is tending. Another character in which I have found little or no variation within a genus is the pattern of the spatha of the male genitalia. With the exception of Thernpon and Tiichostictia, in which genera the spatha It almost identical in form, each of the other genera has its own peculiar form of the spatha. I have refrained from using this character in my keys for distinguishing the genera since there is no corresponding character in the female, but for all that, it is a char- acter that must be taken into consideration. In addition to the char- acters cited above, I have made use of the pubescence of the eyes, the form of the dorsal border of the clypeus, and of certain differences m the venation of the wings. In the accompanying table I have attempted to show my concep- tion of the relationship existing among the several genera included in this revision. I have not, however, included in the table the genus He7nidida, for the simple reason that I have had no opportu- nity to study a single specimen of Monedula singularis Taschenberg. 'J'he difficulty met in an attempt to show exact relationships among genera by a linear arrangement becomes apparent at once. If. as is generally conceded, the presence of unimpaired ocelli labial palpi PEOCEEDINGS OF THE NATIONAL. MUSEUM VOL. 75 of four segments and maxillary palpi of six segments, and three spines on the eighth sternite of the male indicate primitive condi- tions in this group, then the first three genera included in the table certainly belong together and are more closely related to one another than to any other of the genera considered. The other genera have become specialized along one or more of the three lines indicated above, and by selecting one of these three lines of specialization on which to base the main divisions we get a different grouping of the genera from that which would have been obtained had we selected either of the other two. It is my opinion that by making the variation in the form and extent of the reduction of the anterior ocellus the main point of departure the relationship existing among the several genera can best be brought out when a simple linear arrangement is employed. I have used such an arrangement in the table submitted. • GENERIC REVISION OF THE FOSSORIAL WASPS PARKER H » 3 -3 32 9 S3 ft— >.4'OT3 03 »« d d 13 O O SaaM !2 c3 '-3 d as S3 •?« •? d-ci dtS <1 03 C3 > o d.2 O CO 3ja . o o , a d S d o o » ® g CS 9« d Aa^ d So <1 ag S-2 «^-9 s^l 155 ; ffl ©a di n u5 -•2^.5 '§:§ = ft C 60 2»-a II gl <1 2 ^o 73 -O «9- bo ^ — o o .Q ,2 c ^ d ® o ^& o d2 o .2 " =3 -o 0! -2 •S|as2"~^ , -oSat;3 3 c ij S NATIONAX.