MYDAIDiE 



603 



X. MYDAID^. 



Orthorrhaplious brachycerous almost eremochsetous (excepting on legs) 

 flies of gigantic to moderate size, distinguished by their pecuUar venation 

 and antennse. 



Fig. 331. — Syllegomydas ductus J. x 3. 



Head broad and short, pubescent but absolutely without bristles, and well 

 separated from the thorax by a narrow neck. Face pubescent, but hardly with a face- 

 beard. Frons and vertex sunk between the eyes ; ocelli indistinct, unless on an 

 elevation on the middle of the frons far away from the vertex. Proboscis usually 

 rather thick and with large sucker-flaps, but ranging to very long and thin with 

 scarcely any sucker-flaps ; palpi usually apparently absent, but sometimes long, thin, 

 and one-jointed. Eyes bare, widely separated in both sexes, and without any 

 enlarged facets in either sex. Antennse porrect, approximated or in fact almost 

 touching at the base ; two basal joints normal, the first longer than the second 

 and bearing obvious bristles or hairs ; third joint usually elongate and bearing at its 

 end a very large and usually long apparently jointed characteristic clubbed style, 

 but sometimes forming a large hatchet-shaped joint which bears no style 

 (Dolichogaste7-). 



Thorax rather quadrangular with the humeri strongly prominent, absolutely 

 without bristles, though with coarse pubescence on the sides of the disc or 

 occasionally with moderate pubescence on the disc ; pleurae sometimes with rather 

 abundant pubescence on the pteropleurse, or sometimes with a tuft of hairs on the 

 metapleurge. Scutellum small and unarmed, forming a narrow parallelogram which 

 does not project or overshadow the very large metanotum. 



Abdomen elongate with seven segments besides the genitalia, and absolutely 

 without bristles or long bristly hairs ; basal segment rather broad and often with 

 a projecting hump at each front corner. Genitalia of the male not large nor much 

 produced, and with small foliaceous lamellae which are often hidden ; ovipositor 

 produced but never elongate, and in all European species with a terminal circlet of 

 spines. 



Legs nearly always strong and stout but sometimes the anterior pairs only 

 moderately so ; hind femora usually thickened but occasionally almost slender, and 

 almost always distinctly serrate or spinose beneath ; tibiae often bearing a row of 

 small spines (not spicules as in many Tromopteka nor long strong bristles as in 

 Energopoda) either on the hind or middle tibiae only, or on all the tibiae, and 

 apical spines sometimes occur on all the tibiae, while the hind pair usually have a 



