HOW TO KNOW THE IMMATURE INSECTS 



36b. At least maxillary stridulating teeth present. 



Fig. 214 Family SCARABAEIDAE 



The larvae of many Scara- 

 baeids live in dung or other 

 decaying organic matter and 

 are of little consequence ex- 

 cept to act as scavengers. 

 Many others feed on the 

 roots of growing plants and 

 are highly destructive. 



Fig. 214. o. White grub; b, Maxilla. 



37a. 8th abdominal segment of normal form and not terminal; 9th 

 abdominal segment large. (See Fig. 215) 38 



37b. 8th abdominal segment large and terminal; 9th abdominal seg- 

 ment vestigial. (See Fig. 217) 39 



38a. 10th abdominal segment almost obliterated and without soft, ter- 

 minal prolongation; ocelli absent. 

 Fig. 215 Family DASCILLIDAE 



Fig. 215. Dascilius davidsoni Lee. 



This is a group of small to med- 

 ^ ium terrestrial and aquatic beetles. 

 The larvae have been found in 

 pasture land. Some 500 species 

 are known. 



38b. 10th abdominal segment well developed, with soft terminal un- 

 paired, 2-segmented and retractile prolongation; 5 ocelli on each 

 side. Fig. 218 FamUy HETEROCERIDAE 



Fig. 216. Heterocercus ventrolis Melsh. 



The family is very widely 

 distributed and about 100 

 species are known. The 

 larvae live in galleries which 

 they excavate in the mud 

 bordering pools and streams. 



89 



