INJURIOUS TO CUCUMBER, SQUASH AND MELON 125 



The young caterpillar differs from the later stages in having 

 the head larger in proportion to the body, in being more hairy 

 and in having the body more tapering behind. When full- 

 grown, the caterpillar (Fig. 76) is about an inch in length ; the 

 body is white and the head dark brown with an inverted V- 

 shaped white mark. The burrows occupied by the larger larvre 

 are usually wet, slimy and partly filled with excrement ; decay 

 often ensues and hastens the death of the vine. The greater 

 part of the excrement, however, is thrown out of the burrow 



Fig. 76. — The sfiuash-vine borer (X 1^). 



through holes in the stem. These coarse, yellowish grains of 

 frass collect on the ground under the vine and are usually the 

 first indication that the plant is infested. The caterpillars 

 reach maturity in about four weeks in the latitude of New 

 Jersey. When mature the caterpillar leaves the stem, enters 

 the ground one or two inches and there constructs a tough 

 silken brownish or blackish cocoon into the outer layers of 

 which particles of dirt are incorporated. The cocoon is about 

 f inch in length. After making the cocoons, some of the cater- 

 pillars soon transform to pupae, while the others remain in the 

 larval condition until the following spring. Those that pupate 

 soon after spinning the cocoon usually transform to moths 



