— 151 — 



venter, especially m the female, gives a decidedly Po/is/es-Vike aspect to 

 this remarkable form, and it also bears some resemblance to our forms 

 of Ah'dus and Beryius. It can hardly be the species E. nigriceps, de- 

 scribed by Prof Westwood, London Entom. Soc. Trans., v. II, 1837, 

 p. 22, pi. II, fig. 7, as the type of his genus ; but the proportions in form 

 there given would seem to approach very nearly to those of our species, 

 notwithstanding the disparity in the colors of the two insects. 



The genus Xenelus established by Mr. Distant in the Biologia Cen- 

 trali-Americana will, no doubt, prove upon actual comparison of the 

 types to be the same as this Eucerocoris of Prof Westwood. In the 

 former, the eyes are stated to be "contiguous to the anterior margin of 

 the pronotum," but in all the numerous specimens that I have examined 

 only the immature females seem to have a corner of the eye in contact 

 with the pronotum. In the males, the eyes are, as in many genera of 

 Capsidce, widely remote from the collum of the pronotum, while in the 

 females they are in direct contact therewith. No contact is seen in the 

 figure oi Xe7ieiux bracteatur Dist,. which exactly agree in form with our 

 species o{ Eucerocoris described above. 



-» » •»• 



An interesting Ncaa^ Genus of South American Tachinidae. 



By Prof. S. W. WiLLrsxoN. 



In a valuable collection of South American Diptera, received from 

 Mr. H. H. Smith for study, I have found a very singular species of 

 Tachinidce, of suflficien: interest to justify its description in advance of a 

 more extended paper now in preparation. The species differs not much 

 in structure from some o{ Jurinia, save in the antennae, but the structure 

 of these, at least in the male, is the most remarkable that I have seen in 

 the order. The peculiarity of structure is essentially sexual, though the 

 female antennce shows a trace of the male structure, sufficiently unique in 

 itself to distinguish the species generally with sharpness. The singular 

 development is in the third joint alone, which as a whole is of very large 

 size and composed of elongate slender rods enclosing a deep narrow 

 basket-like cavity. How such a peculiarity should have arisen, and what 

 service it can be to the male fly are speculations, which, like those on 

 many other striking sexual peculiarities of structure so common among 

 Diptera, must for the present remain as speculations. Here, as is so 

 generally the rule among Diptera, and indeed among all forms of animal 



