2OO Bugs, Cicadas, Aphids, and Scale-insects 



will go whirling around the bright globe of light, casting large fleeting 

 shadows on the ground below. The giant in the pool's depth and the giant 

 in the giddy swarm at the light are one and the same, viz., the giant water- 

 bug or electric-light bug, a member of the family Belostomatidae. Most 

 of its life is passed in the water; it hatches from eggs deposited under water, 

 lives its whole immature life in the pool, and only comes out for a short flying 

 season to find mates or a new pool. Two very large species of this family, 

 both common in this country, are Belostoma americana (Fig. 275) and Benacus 



griseus, distinguishable by the fact that 

 the former has a groove on each front 

 femur for the tibia to fit in when folded. 

 A smaller kind, more oval in shape, is the 

 commonest form on the Pacific slope. 

 This is Serphus dilatalus, the toe-biter, 



FIG. 275. 



FIG. 275. The giant water-bug or electric-light bug, Belostoma americana. (Natural 



size.) 

 FIG. 276. The western water-bug, Serphus sp.; male with eggs deposited on its back 



by female. (Natural size.) 



which is ij to i inches long and to f inch wide. In the East a still 

 smaller form, Zaitha fluminea, is common. This is a little less than i 

 inch long. All these Belostomatids are fiercely predaceous, capturing 

 aquatic insects, tadpoles, etc., and are armed with a short, strong, pointed 

 beak with which a serious puncture can be made. They secrete themselves 

 beneath stones or rubbish, whence they dart out on their victims. A con- 

 siderable amount of poisonous saliva enters the wound made by the beak, 

 and probably aids in overcoming the prey. The larger species attack 

 young fish, seizing them with their strong grasping fore legs and sucking 

 their blood. They can do much injury in carp-ponds or in garden-pools 

 where fishes are kept for pleasure. The females of the species of the 



