DOLICHOPID.E. 147 



beset with longer bristles chiefly towards the incisures. The 

 ventral portion of the first segment is obsolete. In the male 

 often a sixth, rarely even a seventh segment appears above, before 

 the hypopygium, which is usually large, bent in under the belly, 

 sometimes imbedded or concealed in a cavity behind the fourth 

 ventral segment, at other times entirely disengaged from it, and 

 is furnished with a number of appendages varying greatly in size 

 and form : these have been particularly examined in several 

 species, and described, by Cuvier, in the second volume of the 

 1 Journal de Physique ' (Bosc's) . In the female the vagina is 

 retracted, very short, its upper lid armed at the edge with a row 

 of (about 8) teeth, or short flattened spines, implanted in distinct 

 sockets, almost concealing the very short tentacula below them, 

 which consist each of one ovate piece. The legs are generally 

 long and slender ; the intermediate pair usually the longest, the 

 hind pair the thickest ; the fore pair seated at some distance from 

 the intermediate, but their coxae long enough to touch the latter. 

 There are usually some scattered spines or bristles on the sides of 

 the tibiae, as well as at the tips at least of the posterior pairs, and 

 the posterior femora mostly bear a single spine in front near the 

 tip. The males are often distinguished from the other sex by the 

 form and pubescence of the legs, particularly of the tarsi. The 

 onychia are of moderate size, flat, membranous, pubescent; the em- 

 podium recurved, usually slender, almost setaceous, and finely 

 pubescent ; in ApJirosylus more thickened. 



The present family, being one of the most distinct among the 

 Erachycera > was early indicated by the consecutive position of the 

 species in general in the works of Fabricius. Harris, in his 

 'Exposition of English Insects' (1782), seized with a keen eye 

 the distinctive veining of the wing for the type of a subdivision 

 of the Linnsean genus Musca (Order V. section 3). The genus 

 Doliehopus was first characterized by Latreille in 1796, and 

 converted into a family (Dolichopodes) in 1809; but the true 

 limits of it were not accurately defined until the appearance of 

 the fourth volume of Meigen's great work in 1824, since which 

 time there has been no difference of opinion in this respect. 



The affinities of the family are more difficult to determine with 

 certainty, on account of the strong characters which separate it 

 from the rest. On the whole, it seems to make the nearest ap- 

 proach to those Empidfs in which the maxillae become obsolete ; 

 and in particular the genus Chersodromia in that, and ApJirosylus 

 in the present family, offer points of resemblance. Agreeing with 

 the Empida and Lonchopterida in the disappearance of the axillary 



