ASILIDiE 617 



Sacken's superfamily Enekgopoda in his sense, as I consider the 

 MiCEOPHONA {Empidce and Dolichopudidcc) less allied to the Asilidce. than 

 the latter are to the Mydnidct: and Thcrevidce. The remarkable circlet 

 of stout spines which occurs at the end of the ovipositor in some 

 Anthracince, the Thcrevidce, many Mydaidce, and some Asilidce in all 

 probability shows close affinity. 



The Asilidce form the largest family in the Beachycera, as in 1868 

 Schiner reckoned the number of described species to be 1996, and since 

 then about 1000 more have been described, so that after making requisite 

 allowance for synonomy about 2700 known species must exist. Their 

 size and habits have no doubt attracted collectors, but amongst the smaller 

 and more obscure forms a very large number of unrecorded species must 

 still remain. In the Palsearctic region about 570 species have been 

 described, but in Britain we recognise only 23, of which 21 have occurred 

 in England, 11 in Scotland (including two which have not been recorded 

 from England), and (as far as I know) only one {Fhilonieus albiceps) 

 in Ireland ; Walker however included in addition N. cyanurus, E. 

 cingulatus, and the species which he called A. forcipatus (by which I 

 think he meant E. rufiharMs) from Ireland, and Dioctria celanclica from 

 Scotland. A few more species may occur in Britain, Zetterstedt having 

 described 43 from Scandinavia, and our sandhills on the Welsh coasts 

 might produce even the large S. diadcma, which is reputed to have been 

 taken near Swansea. 



The species are all exceedingly predaceous and are said to always catch 

 their prey upon the wing. I have seen Neoitamus cyanurus sitting at the 

 end of leafless twigs ready to dash out and capture the little green Oak 

 Tortrix (T. viridana) but not hesitating to seize a comparatively large 

 Geometer ; Asilus crahroniformis rests motionless on rather bare patches 

 on heaths or pastures, but is evidently keenly alert for any passing insect 

 and is ready to seize any large Dipteron (such as Sarcoj^harja) or even a 

 flying beetle, and when disturbed it only flies a short distance and then 

 settles again motionless. Exotic species have been seen to seize small 

 Dragon-flies (Agrionince) and Williston states that he once saw a female 

 seize a pair of her own species and, thrusting her proboscis into the 

 thorax of the male, carry off both together. The larvte have been 

 found in rotten wood, under bark (vide note on Zaphria fiava), or in 

 decomposing vegetable matter, where they feed upon the larvse of other 

 insects, etc., or possibly act as scavengers. Loew long ago (1847) 

 remarked the difference in habits between the quick-flying powerfully 

 armed Asilince and the slow-flying weaker DcfsyjJOf/onince, comparing the 

 former to Eoad-Eobbers and the latter to Bush-Thieves. Prof. Poulton 

 (Trans. Ent. Soc, Lond., 1907) has collected all the details he could 

 obtain as to the prey of the various species and has shown that there 

 is in many cases a considerable (and sometimes remarkable) mimicry 

 between the preyer and the prey, and that certain genera aflect special 



