HOW TO KNOW THE IMMATURE INSECTS 



117a. Abdominal segments soft, with short conical gills; last 3 ab- 

 dominal • segments attenuate, not forming a breathing pocket. 

 Fig. 322 Subfamily Spercheinae, HYDROPHILIDAE 



The hydrophilids include many spe- 

 cies of rather widely diversified forms 

 and habits. The species of this sub- 

 family are exotic. 



Fig. 322. Spercheus emor- 



ginatus Schall. (Redrawn 

 from Boving & Craighead) 



117b. Abdominal segments with well developed plates; last 3 ab- 

 dominal segments forming a breathing pocket. 

 Fig. 323 Subfamily Hydrochinae, HYDROPHILIDAE 



The members of this subfamily are 

 small and in consequence frequently 

 overlooked. The species pictured is 

 known from the Great Lakes area. 



Fig. 323. Hydrochus squamifer 

 Lee. 



118a. Hypopharyngeal sclerome absent; mandible without a real molar 

 structure 119 



118b. Hypopharyngeal sclerome present; 

 mandible with a definite molar struc- 

 ture. Fig. 324 142 



Fig. 324. a, Mandible; b. 

 Dorsal aspect of labium 



119a. 9th abdominal tergum armed with a pair of cerci or an unpair- 

 ed spine. Fig. 325 Family MORDELLIDAE 



There are about 800 known spe- 

 cies. Some larvae are found in ter- 

 mite nests and the burrows of stem 

 and wood-boring insects. They are 

 possibly predacious, but that has 

 been questioned. 



Fig. 325. Tomoxlo bjdentota 

 Say. 



118 



