296 THEKEVIDjE. 



moderately large; in 2 l n g? shining, with a circlet of spines at 

 tip as in many ANTHRACIN^; and ASILID^. 



Legs rather long and thin, with bristles of moderate size ; 

 anterior tibiae with two or three longitudinal rows of bristles, 

 hind tibiae with four rows ; all tibiae with a circlet of apical spines ; 

 pulvilli two or none, empodium reduced to a thin bristle or 

 absent. 



Wings witli a rather uniform venation ; 1st and auxiliary veins 

 not extending much beyond middle of wing ; praefurca beginning 

 at some distance before base of discal cell ; 2nd vein simple ; 3rd 

 forked, the fork generally including the wing-tip upper branch of 

 4th vein forked ; 5th vein forked ; anal vein present and generally 

 axillary vein also ; anterior cross-vein placed at about middle of 

 discal cell, which latter is always present ; posterior cross-vein 

 present. Two submarginal, five posterior cells, 4th sometimes 

 closed. " Squamae with only the alar pair developed, but they 

 are rather large and peculiarly folded, so that the strongly-defined 

 margin is angled about the middle, and gives the impression of 

 there being two pairs of squamae." (Verrall.) 



Life-history not definitely known, although on several occasions 

 specimens have been alleged to have been bred from Lepidopterous 

 larvae (Sphinx, Triph&na, Aleiicls). Larvae very elongate, cylin- 

 drical, very active, vermiform, with exserted head ; body apparently 

 of 19 or 20 segments, probably caused by subdivision of true seg- 

 ments, ainphipneustic, with prothoracic spiracles on 2nd body- 

 segment, and a posterior pair at sides of 4th segment from tip ; 

 last segment small; no pseudopods, but a few fine bristles on first 

 three body-segments. Pupa free, bearing antennal sheaths on 

 front side of head. The larvae are found in the earth or in sand, 

 sometimes in decaying wood, occasionally in fungi, turnips, or 

 dung; they are said to be carnivorous. The perfect insects occur 

 chiefly in shady places, on bushes and low-growing plants, 

 Walker and Williston stating that they prey on other insects, 

 although no sufficiently attested case of the kind is known ; and 

 they are also stated to be cannibalistic in captivity. Beling and 

 Bouche have supplied most of our knowledge on this subject. 



The THEUEYID*; occur in all parts of the world, but are most 

 numerous in Europe and North America. They are easily 

 recognised by their usually furry appearance, subconical shape, 

 and unmarked wings, and can be distinguished from their nearest 

 allies, the BOMBYLIID^;, by the five posterior cells and the presence 

 of the posterior cross-vein. Many species are objects of great, 

 beauty; amongst Indian representatives of the family may be 

 noted Psilocephala sequa, Walk., which is covered with nearly 

 snow-white pubescence and performs aerial dances in many places. 

 Although the Indian species (except one or two Psilocephala) 

 appear quite distinct, the family is noted for the exceedingly close 

 affinity of some species, characters which at first sight would 

 appear trivial being constant and of quite good specific value. 



