352 



FAMILY ASILID^. 



(Robber Flies.) (Plate 42, Fig. 5.) 

 These are very common in Australia, and range 

 from small insects, about three-quarters of an inch, 

 to the large-bodied robber fly {Craspedia coriaria), 

 which is one and a half inches long. The legs are 

 strong and covered with stiff hairs. These are 

 insects with swift, strong tlight. The head 

 is clearly cut off from the body and is ver}^ mobile 

 There are no squama? present. They have excellent 

 vision, to enable them to sight a probable victim. 

 The antenna consists of four joints; the fourth joint 

 is bristle-like but fairly thick and terminal, thus 

 differing from some of the other groups. (Plate 40, 

 Fig. 7 b.) The proboscis is fairly long and stout, 

 for these flies are predaceous. Sliarp thus describes 

 them: '* These flies are most voracious, their prey 

 being insects, which they seize alive and impale 

 Avith the rostrum (proboscis). They are amongst 

 the most formidable of foes, and fear nothing, 

 w^asps or other stinging insects being attacked and 

 mastered by the stronger species witiiout difficulty. 

 They have been observed to capture c\'cn dragon 

 flies and tiger beetles. As is the case with so many 

 other insects that pi'cy on living insects, the! 

 appetite in tlie Asilidic seems to be insatiable; 

 a single individual has been observed to kill eight 

 motlis in 20 minutes." 



In many Asilids the abdomen tapers to a point. 

 Little is known of the life history of the larvae. 

 Some species are said to be predaceous on other in- 

 sects and live in the ground. 



