ORDER COLEOPTERA. 



113 



Family Platypsyllidse. Body flat, like a cockroach; eyes and 

 mandibles wanting. Platypsyllm castoris Ritsema is, both in its larval 

 and adult stages, a parasite of the beaver. 



Family Hydropbilidse. Body oblong, oval, convex, or hemispheri- 



FIG. 136. Hydrophilus; its egg-case and larva. Natural size, 

 cal; palpi often very long; mostly aquatic; larvae carnivorous. 

 drophilus triangula/ris Say; Spkceridium scarabcemdes (Linn.). 



Adephaga. 



This group has been already briefly defined on p. 08. 

 The water and ground beetles are 

 usually carnivorous both in the 

 larval and adult stages, though 

 many are phytophagous. 



Family Gyrinidee. Body oval; an- 

 tennae irregular, very short; eyes di- 



jj rm. 



vided so that they appear as four. The 

 whirligig beetles are seen in groups 

 gyrating and circling on the surface of 

 ponds and streams, and when caught 

 give out a disagreeable milky fluid. 

 Gyrinus borealis Aube. 



Family Dytiscidae. Like Carabids ex- FlGS ^,\^. -Gyrinus bor.-aUs 

 cept in those characters which adapt and larva of another species. 



