327 
WATER BEETLES IN' RELATION TO PONDEISH CULTURE. 
Fig. 137. — Head of larva of T. glaber. Fig. 138. — Head of larva of T. mixtus. Fig. 139.— Ventral view of pupa of lateralis. 
Fig. 140.— The same, glaber. Fig. 141.— The same, mixtus. Fig. 142.— Fag of egg case of mixtus. 
