160 . Psyche [Oct.-Dec. 



ON EUMENES ALLUAUDI PEREZ, A PEECIIsTCTIVE 

 WASP OF THE SEYCHELLES (HYMENOPTERA). 



By J. Bequaekt, 

 American Museum of Natural History, New York City. 



In my Catalogue of Ethiopian Diplopterous Wasps, published 

 in 1918,1 J ]^ave attempted to correlate the various described forms 

 of African Eumenes. In many cases, where specimens were not 

 available for study, my conclusions were based on such inferences 

 as could be made from published accounts, and were therefore 

 only tentative. Eumenes alluaudi J. Perez,^ for instance, I re- 

 garded at the time as one of the color variants of Eumenes lepele- 

 terii Saussure, to which it was said to be related by the author 

 of the species. Through the courtesy of Mr. A. S. Eohwer, I 

 recently had opportunity to examine a series of specimens of 

 E. alluaudi in the U. S. National Museum collection, and was 

 surprised to find that this wasp is structurally very distinct from 

 any of its congeners. Since it apparently is restricted to a very 

 small range in the Seychelles and neighboring islands, and thus 

 affords a typical illustration of the effects of oceanic isolation upoTi 

 the appearance and preservation of specific characters, it may be 

 useful to redescril^e the form and to figure some of its most note- 

 worthy peculiarities. 



Female. Length (head-|-thorax-|-tergites 1+3) 21 mm. 



Decidedly more slender than E. maxillosus, strikingly so in the 

 abdomen. Head (Fig. 1&) from front view about as high as 

 broad, due to the lengthening of the clypeus. Clypeus distinctly 

 higher than broad; its apical free portion a little longer than its 

 basal part and with more deeply concave sides than in E. maxil- 

 losus; its apical margin almost straight, slightly curved inward, 

 with pronounced, but blunt lateral angles. Vertex without fovea. 

 Eyes bare. Posterior ocelli about as far from each other as from 

 the eyes. Mandibles shaped much as in E. maxillosus; long and 

 slender, beak-like, the inner margin with three slight notches; 

 near the base of the inner margin an indication of the raised 

 fold which is so prominent in the male. Antennae and mouth- 



' Bull. American Mus. Nat. Hist, 39, 1918, pp. 274-2S3. 

 2 Ann. Soc. Ent. France, 64, 1S95, p. 206. 



