26 



Segments 

 and ap- 

 pendages 



The Larva of Chirononius 



Canada balsam. Some of the heads should be broken 

 up with needles. For surface -views, larvae hardened in 

 Flemming's solution or some similar fluid are particu- 

 larly useful. Further descriptions of methods are given 

 in the Appendix. 



The body (fig. i) consists of a head and twelve seg- 

 ments \ The head is rather small, and defended h^ 

 a dense armour. The first three segments behind the 

 head correspond to the thorax of the fly, and are distin- 

 guished as pro-, meso-, and metatliorax. The prothorax 

 has a pair of stumpy claw-bearing feet. The only other 

 pair of feet, the anal feet, are carried on the last segment. 



Fig. 15. — Jjsxrva oi C'!iir<mO]n>(s dorsaUs. A, head, dorsal view. B, ditto, front 

 view. C, edge of labium, with its teeth and papillae. (From MialFs Nahiral 

 Hist or !/ 0/ Aquatic Insects.) 



The larval 

 head. 



The larval head (figs. 15, 17) is protected on its upper or 

 dorsal surface by three plates, one median and two lateral. 

 The median plate (clypeus) carries the labrum, which 

 hangs like a flap in front of the mouth, and can be bent 

 backwards. The epipharynx or hind surface of the 

 labrum, which looks towards the mouth, is furnished with 

 an elaborate armature, which will be better understood 

 by reference to fig. 16 than by any explanation in words. 



' Tliis is the usual number in Neniocerau larvae. Pericomn and Pliah 

 crocera have only eleven segments behind the head. 



