comparative ChcBtotaxif. 515 



bristles (Laphria), often hardly distinguishable from 

 hairs, and a characteristic fan-like row of metapleural 

 bristles. (Mik says that Loew called it Haarschirm in 

 the Empidce). 



There is a mine of systematic characters yet to be 

 explored in the study of the chaetotaxy of the Asilida. 

 As an instance I will cite Dasypogon diadema and D. 

 teutonus, placed by Loew in the same ultimate sub- 

 division of Dasypogon (sensu stricto). A glance at the 

 cliEetotaxy of these species shows that D. teutonus has 

 no bristles on the scutellum, while in D. diadema the 

 scutellum is beset with 4 — 6 strong macrochsetas. A 

 further examination reveals other abundant differences 

 in the arrangement of the bristles on the thorax and 

 the legs ; it discloses at the same time other characters 

 peculiar to each of the species, — in the shape of the 

 abdomen, in the structure of the forceps of the male, 

 &c., — all of which tend to prove that these species 

 belong to two very distinct genera. And yet when we 

 read the descriptions (not excepting even those of Loew) 

 we find almost nothing but colours mentioned. When 

 Eondani (Prodr., i., p. 157, and Corrigenda, iv., p. 7) 

 introduced a new genus for D. diadema {Cheilopogon, 

 afterwards called Seilopogon), he did so merely because 

 this species has the 4th posterior cell closed ; in con- 

 sequence of which other writers have placed in that genus 

 all the DasypogonincB with a hook on the anterior tibiae, 

 which have the 4th posterior cell closed, without 

 any regard to other characters or to other genera which 

 may have been previously established for such species. 



MidaidcE. — They are entirely destitute of macrochaetae, 

 and I have shown (Berl. Ent. Z., 1883, p. 292) that, for 

 this as well as for other reasons, the relationship between 

 them and the Asilidce is not as close as is generally 

 supposed. 



EmpklcB. — The characteristic bristles are often, as in 

 the Asilidce, indistinct among other hairs ; but whenever 

 these are less dense, some of the bristles become easily 

 recognizable ; one larger humeral, and several smaller 

 ones ; post-humeral bristles ; a fan-like metapleural 

 row, similar to that of the Asilidce, &c. 



Bomhylidce. — It is only in a very few genera of this 

 extensive family that the macrochaBtae are differentiated 

 in a more or less striking manner from ordinary hairs. 

 Thus in Toxophora there is a number of conspicuous 



