50 



THE ORDER OV COLEOPTERA. 



TRir.E n. 



PEEDAOEOUS WATEE-BEETLES. 

 Carnivora aquatica, Hydradephaga,* MacLeay. 



These insects are distinguislied from those of the first tribe by their 

 feet being' fitted for swiininiug, the two hinder pairs beinji^ much flat- 

 tened and margined with long hairs or ciliie. 



This tribe contains two families. 

 A. Antennte slender, filiform ; hind legs long, and attached to the 



breast far behind the other two pairs Dyttsctd^. 



A A. Antennje very short and ])eculiar ; the three pairs of legs attached 

 at nearly equal distances from each otlier ; middle and hind 

 legs very short Gyrinid^. 



Family III. DYTISCIDvE. 



This family is founded ujion the genus Bytiscus, of LinnpBus, derived 

 from a Greek word meaning a diver, and given to these insects on ac- 

 f^'g- ^"'J count of their eminently 



aquatic habits. They are of 

 an oval and somewhat flat- 

 tened form, and of a brown- 

 ish - black color, generally 

 with a dull glaucous or sea- 

 green tint. Th some species 

 the thorax is dull yellow, 

 either with or without black 

 cross-bars. One of their 

 most distinctive and easily 

 recognized characters is the 

 position of the middle legs 

 close to the anterior ones, 

 leaving an unusually long 

 . ,. , , ^ space between the middle 



a, larva of 7>. inarginaus ilevouriiig a larva oi 

 Ephemera^ after R«>sel : 6, pnpa of samo — after Rye : c, JJ. j),])(J^ thc hiud leffS. Thcse 

 fascicentris. Say, the detached figure ou the I'ijiht showing _ * 



the grooved elytron of the female: d, the anterior tarsus of insectS are eminently aqua- 

 the male, underside, showing the suction cups; e, same of " ^ 



female— after Kiiey. tic and [jrcdaccous, and may 



be supposed to represent the sharks and other ferocious aquatic ani- 

 mals of the higher classes. 



They have sometimes been found very troul)lesome in artificial fish- 

 ponds, attacking the young gold and silver fishes and eating oil' their 



rtVTieoIJS : 



* From the Greek hudor — water ; and adephagos — ravenous. 



