DYTISCID.E. 



435 



ligula ; /, raeiitum ; g. prosternum, Iront, and h, side view ; ?', 

 under side of the rest of the bod}', sliowing the six ventral seg- 

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

 in Nortliern California, is the sole representative of this family 

 and differs from the preceding family in the metasternum bc- 



'. d J i 



Fig. 379. 



ing truncate behind, and not reaching the abdomen. A, iiiso- 

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

 structure and habits connecting the C ar ah uUb ^\\i\\ the suc- 

 ceeding family. 



DYTisciD.^i McLcay. The Diving Beetles, or Water Tigers, 

 are oval flattened elliptical beetles, which differ from the Cur- 

 abidm in the form of the hinder coxa?, which are very large, 

 touching each other on the inner edge, and externally reaching 

 the side of the body, entirely 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 larva? 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 ott' the tails 

 of tadpoles, while the}' are even known to attack young fishes, 

 sucking their blood. They are known to moult several times 

 four or five days intervening between the first two periods oi 

 moulting, and ten days between the latter. The l)ody ends in 

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

 air, though eight pairs of rudimentary 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 beetle appears, if in summer, or 



