HOW TO KNOW THE IMMATURE INSECTS 



114a. 9 complete abdominal segments; 10 th small. 



(See Fig. 319) 115 



114b. 8 complete abdominal segments; 9tli and 10th reduced. 



(See Fig. 321) 116 



115a. No ocelli or but 1; cardo fused with stipes; coxae small and 

 widely separated. Fig. 319 FamUy HISTERIDAE 



This family consists of 



jy about 3,000 known species. 



b Iv Many of the larvae are pre- 



^ hISS* dacious upon coleopterous 



A \ and dipterous larvae and a 



ai:<!aKfcsMaau^«)-\u'-^*^>i^^ y^ few species attack immature 



stages of Chrysomelidae and 



Fig. 319. a, Hololepta yueateea Mars.; b, Lspidoptera. A number of 



them are myrmecophilous in 

 habitat. 



115b. 6 ocelli; cardo distinct; 

 coxae large, approxi- 

 mate. 



Fig. 320. Subfamily 

 Helophorinae, HYDRO- 

 PHILIDAE 



Fig 320. Q, Helophorus aquaticus L. (Redrawn 

 from Boving & Craighead); b, Maxilla. 



116a. Head elevated; antenna inserted farther from the lateral 

 margin of the head than is the mandible. 

 Fig. 321 Family HYDROPHILIDAE 



a 





This family c o m - 

 prises about 1,700 spe- 

 cies. The eggs of sev- 

 eral genera are en- 

 closed in silken cases 

 and attached to grass 

 or floating objects, but 

 Helochares and Sper- 

 cheus fasten them on 

 their own bodies. The 

 larvae are chiefly vegetable scavengers, but a few species are pre- 

 dacious. The majority of species are aquatic or semiaquatic, but a 

 number of the subfamily Sphaeridiinae are known to be terrestrial. 



116b. Head slightly inclined; antenna inserted near the lateral 

 margin of the head than is the mandible 117 



Fig. 321. a, Choetortria seminulum Herbst. (Re- 

 drawn from Boving Gr Craighead); b. Dorsal as- 

 pect of a half head. 



117 



