THE HEMIPTERA 173 



plants develop the bugs lay their eggs on their under surface in clusters 

 which vary greatly in the number of eggs composing them. The eggs 

 themselves are oval in outline, very convex, and being resin-brown in 

 color are very conspicuous against the green background of the leaf. 

 In a cluster the eggs are not usually so laid that they touch, but somewhat 

 spaced apart in most cases. At intervals before and during the egg- 

 laying period the adults feed on the plants and when they are very abun- 

 dant may seriously injure or in some cases even kill them. 



The eggs hatch on an average in about 10 days and the tiny nymphs, 

 green and reddish in color, begin to suck the sap from the under side of the 

 leaves, at first together, but scattering later. The reddish color of the 

 nymph quickly changes to black and the green gradually becomes more 

 of a gray. Feeding and molting five times results in the production of 

 the adult after a period of from 4 to 5 weeks from the time the eggs 

 hatch, and in the North the adults feed on the plants until fall; then 

 go into winter quarters. In the South the longer seasons which permit 

 an earlier start in the spring and the higher temperature which causes 

 the eggs to hatch more quickly, permit the production, in some cases at 

 least, of two generations each season. 



The injury to the plants caused by the spring feeding of the adult is 

 continued by the sucking of the young. Where these are plenty, growth 

 is checked and the crop reduced. If the plants are killed by frost before 

 the nymphs are mature, they often attack the fruits in order to obtain 

 the nourishment they need to become adult. 



Control. — Contact insecticides are not effective for the adult Squash 

 bug, which has an unusually thick shell. The usual methods for control are 

 the removal as far as possible of all rubbish and places where the insects 

 can obtain protection during the winter; stimulation of growth of the 

 plants by fertilizers and cultivation; protection of the young plants by 

 fine netting until they are so well started that they can thrive despite the 

 bugs; traps of bark or shingles placed close to the plants, under which the 

 bugs gather at night and whence they can be gathered and destroyed 

 early in the morning (this can be begun even before the plants are up) ; 

 egg-masses being easily seen can be quickly found and crushed; and while 

 the nymphs are small, spraying with Nicotine sulfate 40 per cent, 1 part 

 in 400 of water will destroy them. The difficulty in reaching the nymphs 

 on the under side of the leaves with the spray, can in part be obviated 

 by attaching the nozzle of the spray pump to a piece of tubing connecting 

 at its other end with the hose, and bent in a loop so as to give an upward 

 spray. 



In the South one or two very closely allied species also attack the 

 squashes and cucurbits and may be controlled in the same ways. 



Family Pyrrhocoridae. — The insects of this family superficially re- 

 semble the Coreids and are of medium size. Only one is of any economic 



