1865.] 229 



angle from it; in some specimens the basal portions of these veins are 

 so near each other as to appear coalescent ; a careful examination, how- 

 ever, always proves that they run alongside of each other. The seventh 

 vein is nearly straight. 



The forceps of the male, as far as its structure can be ascertained on 

 a dry specimen, seems to be somewhat like that of Elephantomyia, that 

 is, it consists of a pair of subcylindrical basal pieces, to which two pairs 

 of ensiform, horny appendages are attached. The ovipositor of the 

 female has long, slender, almost imperceptibly arcuated valves. 



The relationship of Toxorhina with Elephantomyia and Rhamphi- 

 dia is evident, and principally indicated by the prolonged proboscis, 

 common to the three genera, the absence of the stigmatical cross-vein 

 and the structure of the feet. 



Toxorhina is easily distinguished from Elephantomyia by the neu- 

 ration of the wings, the submarginal cell of which is wanting; by the 

 structure of the antennae, which are 12-jointed and have some longer 

 bristles on the apical joints only, whereas Elephantomyia has long ver- 

 ticils on all the joints, and by the structure of the thorax, the collare 

 being entirely concealed under the projecting gibbosity of the raesono- 

 tum, the mesosternum being unusually developed, and the metanotum 

 also very large and horizontal. 



[At this place a blank was left in my manuscript, in the expectation 

 of an answer from Mr. Loew about the vexed question of the identity 

 or diversity of Toxorhina Lw. and Limnobiorhynehus Westw. I have 

 discussed this question in the Proc. Acad. N. S. Phil. 1859, p. 221, 

 and have reached the conclusion of the identity of these two genera. 

 Since then, the discovery of the two North American species, to be de- 

 scribed below and an important statement of Mr. Loew. in a private 

 letter, about his article on Toxorhina (in Linn. Ent. V) have led me 

 to change my opinion. We have to recollect that, in this article, Mr. 

 Loew united in the genus Toxorhina a single living species, from 

 Porto-Rico, and three fossil species. Of the former, he had only a 

 female, which he figured. The figure shows that the wings have no 

 submarginal cell. As nothing was said in the description, either about 

 the sex or about the neuration of the fossil species, it could be reasona- 

 bly inferred that the fossil species, like T. fragilis, have no submarginal 

 cell. Such, however, is not the case. In answer to my inquiry about 

 this point, Mr. Loew informs me now that all his fossil specimens of 

 Toxorhina are males, and that all have a submarginal cell. Before 

 the discovery of a N. A. species, showing the same neuration (without 

 submarginal cell) in both sexes, this statement of Mr. Loew would have 



