ACANTHOMERIDAE — TABANIDAE. 19 



na: Sargus, Microchrysa : III. Hermetina: Hermetia : IV. 

 Odontomyina : Cyphomyia, EupARYrHUS, Stratiomys, Odonto- 

 myia, Nemotelus, Oxycera, Clitellaria ; V. Pachygastrina : 

 Pachyg aster, Chauna. 



Fam. XIII. ACANTHOMERIDAE. 



Charact. — Basal cells much prolonged ; longitudinal veins not crowded 

 together anteriorly; two intercalary veins always present ; marginal 

 vein running round the whole border of the wing. Oral parts with 

 four bristles, even in the male. Third joint of the antennse annu- 

 late. Tibise without spurs ; empodium developed to a pulvillar 

 form. 



This small family contains only the two genera Acanthomera 

 Wied. and Raphiorhynchus Wied. It differs from the Stratio- 

 myidce by the longitudinal veins not being crowded together ante- 

 riorly, by the marginal vein encompassing the whole border of the 

 wing and by the fourth cell of the posterior margin being closed. 

 It differs from the Tabanidce in the form of the oral parts and by 

 the tegulas being very little developed; as to the oral parts, I have 

 no absolute opinion of my own, but must rely on the communica- 

 tions of others. 



No species of this family has been as yet discovered in N. A. 

 Fam. XIV. TABANIDAE. 



Charact. — Three basal cells much prolonged ; third longitudinal vein fur- 

 cate ; two intercalary veins always present ; marginal vein running 

 round the whole border of the wing ; tegulse rather large. Proboscis 

 of the male with four, of the female with six bristles. Third joint 

 of the antennae annulate, rarely divided into distinct joints, always 

 without style or bristle ; empodium much developed and pulvilli- 

 form. 



The Tabanidce are easily distinguished from the foregoing fami- 

 lies by the structure of the oral parts and by the size of the tegulte. 

 On account of the presence or absence of spurs at the end of the 

 posterior tibise they may be divided into the sections of Pangonina 

 and Tabanina; the former often, but not always, possess ocelli, 

 whereas, according to the observations hitherto made, they are 

 always wanting in the latter section. 



To the Pangonina belongs, firstly, the genus Pangonia Latr. 



