DIPTERA BRACHYCERA 



DERMATINA 



Two pad-like pulvilli only. Neither bristles nor pubescence 

 present in the ordinary sense of those terms, but the femora 

 sometimes spinose beneath, and the tibiae in some Mydaidw with 

 rows of small bristles. Discal vein ending before the wing-tip. 

 Usually leathery looking flies of pedestrian habits or appear- 

 ance. 



Head usually dichoptic, but occasionally {e.g., Scenopmus fenestraUs) 

 holoptic in the male, and without cephalic bristles; frons and vertex 

 usually sunk ; collar or neck distinctly visible though not bristly in Mydaidm, 

 but indistinct in Scenopinidce, and the head not crammed on to the thorax. 

 Face broad, very short in the Scenopinidm, and without the face-beard which 

 is present in vaoMj Asilidon ; jowls usually very small ; ocelli obvious in 

 Scenopinidce but indistinct in Mydaidm. Proboscis usually short and 

 thick, but elongate and thin in some Mydaidce. Eyes quite bare, bulging 

 in Mydaidce, but almost flush with the frons and vertex in Sccnoinnidce ; 

 facets rarely enlarged on the upper or front part in either sex. Antennffi 

 close together at the base and usually rather long ; usually very distinct 

 in the two families, as in the Scenopinidm the two basal joints are short 

 and the third elongate but drooping without any apical style or arista, 

 but in the Mydaidce the antennce are porrect and the basal and third joints 

 are usually elongate, and the third usually ending in a remarkable large 

 long clubbed style ; in all cases the antennae are quite distinct from those 

 of any Teomoptera or Enekgopoda. 



Thorax without bristles or conspicuous hairs, but sometimes with 

 moderate pubescence on the disc, and in the Mydaidce usually with coarse 

 pubescence towards the sides of the disc; pleurse sometimes bare, but 

 sometimes pubescent. Scutellum always unarmed; metanotum large 

 and not at all concealed. 



Abdomen without bristles or obvious pubescence unless about the basal 

 corners. Genitalia of the male moderate in size; ovipositor of the female 

 often with a circlet of strong spines. 



590 



