DYTISCID^. 



435 



ligula; /, mentum ; {/, prostenium, front, and /<, side view; i, 

 under side of the rest of tlie bod}-, showing tlie six ventral seg- 

 ments of the abdomen ; j, anterior tarsus : from Horn) found 

 in Northern California, is the sole representative of this family 

 and differs from the preceding famil}^ in the metasternum be- 



h d j i 



Fig. 379. 



ing truncate behind, and not reaching the abdomen. A. insO' 

 lens Lee. is an anomalous form, being subaquatic, and in its 

 structure and habits connecting the Carabidce with the suc- 

 ceeding family. 



Dytiscid^ McLeay. The Diving Beetles, or Water Tigers, 

 are oval flattened elliptical beetles, which differ from the C'o?*- 

 abiclce in the form of the hinder coxte, which are very large, 

 touching each other on the inner edge, and externally reaching 

 the side of the bodj^, entirety cutting off the abdominal seg- 

 ments from the metathorax, while the oar-like swimming legs 

 are covered with long hairs, and the hinder pair are much flat- 

 tened. The larvae are called "water tigers," being long, cy- 

 lindrical, with large flattened heads, armed with scissor-like 

 jaws with which they seize other insects, or snip oft' the tails 

 of tadpoles, while they are even known to attack j'oung fishes, 

 sucking their blood. They are known to moult several times, 

 four or five days intervening between the first two periods of 

 moulting, and ten daj^s between the latter. The body ends in 

 a pair of long respiratory tubes, which they protrude into the 

 air, though eight pairs of nidiniontary spiracles exist. "When 

 about to transform the larva creeps on to the land, constructs 

 a round cell, and in about five days assumes the pupa state, 

 and in two or three weeks the l)eetle apj^ears, if in summer, or 



