10 



BRITISH BEETLES. 



with a horny front and head, the 

 latter having strong jaws, rudi- 

 a inentary eyes, antennas, and palpi ; 

 they have mostly six hard front 

 legs, and appendages on the upper 

 side, with a fleshy tubercle on the 

 under side, of the last segment. 

 The legs are sometimes wanting 

 entirely, or replaced by fleshy tu- 

 bercles. The body is composed of 

 the head, and, usually, twelve seg- 

 ments, to the first three of which 

 the horny legs are attached, one 

 on each side ; and there is usually 

 a spiracle, or breathing-hole, on 

 Fig. i. each side of all the segments, ex- 



Full-grown larva of v y - ce t th secon d third, and last. 



ttscus marginalis, a com- * 



mon Water Beetle (nat.size). The number of these segments is 



"' Gr0 o U n P eof th C e el ^e f s. rming reduced in the perfect insect, as 



some of them are incorporated in 



the generative organs, etc. In some larvae, also, only 

 eleven segments appear, owing to the non-development 

 of the apical one ; e. g. in Dytiscus mar- 

 ginalis the twelfth segment is formed into 

 two mere appendages. I have remarked, 

 moreover, in this larva, that the lateral 

 spiracles (which are not fully developed, 

 owing to respiration taking place at the 

 tail) are abnormally placed, there being 

 none on the first segment, two on the 

 second, on the under surface of the body, 

 in front of the second pair of legs : none 



Pupa of D. war- , . 



(nat.size). on the third, one on each side of the 



