614 



ENERGOPODA 



XII. ASILID^ 



Fig. 337. — Philonicus albiceps S- x 3- 



Orthorrhaphous brachycerous chsetophorous " Eobber-Flies " of very- 

 large to moderately small size. Habits pedestrian and predaceous, and 

 consequently the powerful legs usually provided with long strong bristles. 

 Eyes bulging and widely separated in both sexes. Third antennal joint 

 simple. Venation rather elaborate. 



Head broad but short, well separated from the thorax ; frons at the vertex more 

 or less deeply sunk between the bulging eyes ; face usuallj^ produced into a facial 

 knob or with a moderately produced upper mouthmargin, and bearing a con- 

 spicuous bristly or coarse-haired face- or mouth-beard or with extensive soft 

 pubescence ; cephalic bristles as a rule indistinct, being usually when present 

 mixed up with adjacent hairs, but sometimes a pair of ocellar bristles and another 

 pair rather behind the first pair can be differentiated ; a row of occipito-orbital 

 bristles or bristly hairs (forming the "festoon") occurs on the upper part of the 

 postocular region, and according to Osten Sacken these bristles are sometimes 

 plumose • ocelli three, usually on a raised tubercle. Proboscis strong and shortly 

 porrected either horizontally or sloping (rarely perpendicular), but not in any way 

 resembling that of the Bomhi/Iidce ; sucker-flaps not fleshy. Palpi composed of one 

 or two joints. Eyes bulging from the sunk vertex, always bare, widely and almost 

 eciually separated in both sexes, and often with the front facets enlarged. AntennaB 

 porrect, approximated or well separated at the base, three-jointed, the third joint 

 usually more or less elongate but never annulated, and usually (but not in the 

 Laphrince) provided with a terminal (never dorsal) sometimes jointed style or arista. 



Thorax narrowed in front, and leaving the head apparently isolated because tlie 

 pro thorax (including the neck) is long, always bearing strong bristles (macrochsetpe) 

 or dense coarse-haired pubescence intermixed in which traces of macrochaetee may 

 almost always be detected. In the simplest form of bristling (Lepfogaster) only one 

 conspicuous praesutural bristle and one supra-alar occur (though the latter is placed 

 so far out on the disc that it may be mistaken for an intra-alar bristle) ; but in the 

 next development of bristles there is an increase in the numbers of the prcesutural and 

 supra-alar bristles, which very soon leads on to the j^resence of postalar, dorso- 



