28 



The Larva of Chironomiis 



sensory spot; beyond tliis are two terminal pieces of 

 nearly equal length, one jointed, tlie other simple ; the 

 number of joints varies with the species. 

 The jaws. In insccts generally the jaws form three pairs of 

 appendages, which somewhat resemble legs in their 

 form, attachment, and mode of development. The man- 

 dibles, or foremost pair, are the least like legs, being 

 unjointed and usually toothed. They divide the food, 

 and may also be used in grasping, fighting, &c. Two 



sm- 



Fig. 17. — Venti'al surface of head of larva. 

 ant, antenna. W(7., mandible, mx p maxillary 

 palp. s)H, submentnm. a', tooth-bearing surface 

 of labrum. (/, striated flap bordering the sub- 

 mentum. 



Fig. 18. — Mandible 

 of larva, with chitinous 

 tendons and muscles 

 attached. /, fulcrum. 



pairs of maxillae follow, which are generally weaker than 

 the mandibles, divided into many parts, and furnished 

 with palps or feelers. The second pair of maxillae may 

 closely resemble the first (Orthoptera, &c.), but they are 

 often greatly modified for special purposes. 



The mandibles of the Chironomus-larva (figs. 17, 18) 

 are strong and toothed, and so placed that in closing 

 they do not move in the same plane, but at angles of 45° 

 with a vertical plane. They are not opposed to each 



