EMPID.E. 87 



ceding ; but the anal areolet is small and not prolonged towards 

 the posterior margin. Sometimes the costal vein is continued 

 more faintly round the posterior margin, in others it vanishes 

 about the tip of the wing. In the remaining genera of the 

 family the cubital vein is simple, as in the families which follow ; 

 and sometimes (as in most of them) there are but two externo- 

 medial veins, more frequently, however, three. But the most 

 important distinctive character of the wings of the Empida is to 

 be found in the disappearance of the rounded axillary lobe, a 

 condition which prevails among the Nemocera, but which this 

 family has in common with the Dotickopida and Lonchopteridce 

 only among the Brachycera. Some genera of the Platypezidd 

 (Platycnemia, Opetid) nearly agree with the Empida in this, and 

 form the transition. And the same peculiarity re-appears among 

 the Arittda in one genus (Leptog aster) , which in other respects, 

 even as to the wings, is abundantly distinguished from the Empida. 

 Among the Syrpkida, also, this lobe is scarcely apparent in the 

 genera Ascia, Spkegina, and Baccha ; but the two families differ 

 so widely in most respects, that it seems needless to particularize 

 the characters which remove them from a place here. The scutellar 

 alulae are undeveloped. The legs vary much in form and clothing. 

 The fore coxae, though inserted at some distance from the inter- 

 mediate pair, are long enough to pass beyond the base of these, 

 and in some genera (Hemerodromia, Phyllodromia), they are as 

 long as the femora. The abdomen, of 7 or 8 segments, is usually 

 compressed in the male, and nearly linear, or subclavate, the 

 appendages of the hypopygium being directed upwards and 

 towards the back. In the female the last segments are generally 

 much attenuated, and the tentacles of the vagina protruded. 



As has been observed, the want of the axillary lobe to the 

 wings distinguishes the Empida from most of the other families 

 of Brachycera. Prom the Dolichopidce they differ in the greater 

 amplitude and completeness of the brachial areolets, and in the 

 number of abdominal segments. The smaller head, with convex 

 vertex, and the slender and often elongated proboscis, destitute 

 of the remarkable cavity at the end, afford subsidiary characters. 

 The unarmed epistoma, rounded tip of the wings, and fewer 

 joints of the aristae, separate them from the Lonchopterida. 



