ORDER DIPTERA: THE NEMATOCERA, ETC. 61 



above, and the body more from the side, resembles a Culex 

 larva (i) in being pigmented ; (2) in having on the dorsal 

 surface of the 8th abdominal segment a long breathing-tube 

 through which the tracheae pass ; and (3) in the general shape 

 of the head. The head, however, is characterised by the 

 closer setting of the antennae, and by the presence on the 

 clypeus of a projecting pencil of long stiff bristles instead of 

 a pair of mouth-brushes. In other respects the larva agrees 



//Ws i,„,„ 



nerve-cord 



~1 — ^-t- 



Fia. 18.— Larva of Mochlonyx. 



with Corethra, having (i) the paired, pigmented tracheal 

 floats in the thorax and the 7th abdominal segment ; (2) the 

 vertical ventral caudal fin, formed by a series of articulated 

 hairs, on the 9th abdominal segment ; and (3) the prehensile 

 antennae. The antenna, however, is even more efficient of 

 its kind, as it ends in three or four long, stiff grapnels of 

 great strength. The caudal fin also differs from that of 

 Corethra, as the individual bristles are branched. 



Subi"amily II. — CULICIN^. 



Theobald, making the Culicines a separate family, has 

 divided them into ten groups, which he regards as subfamilies. 

 Some of these groups are well defined, others are not ; while 

 some of them, which severally include one or two species, are 

 based upon an overrating of characters which, though in 

 a way striking, are, from a broad zoological standpoint, 

 trivial. 



For our purposes the grouping of these annoying insects 

 in four sections is recommended as follows : — 



("Proboscis bent like a pot-hook ; very large mosquitoes 

 A. ] = Megalorrhini. 



IProboscis not bent like a pot-hook = 2. 



