HOW TO KNOW THE IMMATURE INSECTS 



15b. Galea never inserted on the palpifer; often ab- 

 sent or fused with the lacinia; abdomen always 

 with 9 to 10 distinct segments; if the mandible 

 is serrate, the cerci absent or 1-segmented. 

 Fig. 183 16 



Fig. 183. Maxilla. 



16a. Mandible with a usually large, asper- 

 ate or tuberculate molar part. ' fe. ?r^°^-'« 

 Fig. 184 17 



Fig. 184. Two mandibles. 



16b. Mandible without asperate or tuberculate molar part, usually 

 without molar part 21 



17a. 10th abdominal segment provided with a pair of recurved hooks. 

 Fig. 185 SubfamUy Limnebiinae, HYDROPHILIDAE 



C^cA The members of this small sub- 



^ family are for the most pdrt found 



on the Pacific coast, and are com- 

 paratively small in size. 



Fig. 185. a, Ochthebius mipres- 

 sus; b. Tip of abdomen. 



17b. 10th abdominal segment without terminal hooks but sometimes 

 with a pair of long setae 18 



18a. Spiracles absent; balloon-like appendices on pro thorax, 1st and 

 8th abdominal segments; antenna very short and 2-segmented. 

 Fig. 186 Subfamily Hydroscaphinae, HYDROPHILIDAE 



It is a small subfamily, com- 

 prising only 4 or 5 species adapt- 

 ed for an aquatic life. They oc- 



^<5;5'CA'\^ /T 1/^ a.?\Sj^^\ ' ^^^ ^""^ running water, including 

 /7^^:<X>f^^-^.lE ^^ILSk-^' j^Q^ springs. The one American 



species is found in our South- 

 Fig. 186. Hydroscopho natons Lee. west. 



18b. Spiracles present; no balloon-like appendices; antenna 3-seg- 

 mented 19 



79 



