NATUKAL CHARACTER. 55 



less sharp point ; the first segment is either more conical, or more 

 cylindrical, and then usually thick at its base, or it is quite flat ; 

 in most species it is hairy, in others it is beset with hairs at the tip 

 only ; in others again is quite bare ; its length varies exceedingly 

 in the various species ; the second and the third segments of the 

 borer are always bare. To the length of the borer of the female 

 corresponds that of the thread-like penis of the male. The hairs 

 of the body are sometimes fine and short, sometimes coarse and 

 long ; in the latter case the posterior margin of the abdominal 

 segments is generally beset with bristles, which in the species 

 having fine and short hairs, are either totally wanting or are pre- 

 sent only at the posterior borders of some segments, most frequently 

 on that of the last. 



The legs are always of moderate length, and of a rather robust 

 structure ; they are beset everywhere with short hairs, which be- 

 come longer on the upper side of the posterior tibiae of some species. 

 There are usually some longer bristles on the under side of the 

 anterior femora, and frequently also on their upper side ; similar 

 bristles exist on the posterior femora of several species, and some- 

 times even on the middle femora. The tips of the middle tibiae 

 are always spurred ; otherwise, the tibiae have no bristles. It is 

 very characteristic for all the Trypetidce that the erect bristles 

 are totally wanting, which some allied families, for instance the 

 Sapromyzidce, possess on the outside of the tibice, not far from the 

 tip. The first joint of the tarsi is always prolonged. The claws 

 and pulvilly are small, and of equal form in both sexes. 



The neuration of the wings is that of Acalyptera in its highest 

 perfection, and shows many characters peculiar to this family. 

 The auxiliary vein is separated from the first longitudinal vein, 

 though often- approximated to it, especially in some Dacina; it 

 never runs in the usual way, that is, at an acute angle and with 

 equal distinctness as far as its end or even incrassating towards the 

 border of the wing, but turns suddenly towards it, and, at the 

 same time, becomes much more indistinct, the more so as the 

 space between its end and that of the first longitudinal vein is 

 incrassated. At the place where it runs into the border of the 

 wing, the latter bears a small marginal spine, quite indistinct in 

 many species, and which cannot, therefore, be considered as one of 

 the characters of the Trypetidce. Generally the whole length of 

 the first longitudinal vein is beset with bristles ; this is also most 



