90 APPLIED ENTOMOLOGY 



land in which to make their burrows, and feed on plant roots, earth worms 

 and insect larvae. The "Changa" (Scapteriscus vicinus Scudd.) of Porto 

 Rico attacks the roots of various crops in that island, causing much 

 injury, and has recently been discovered along the sea coast of some 

 of the Southern States where it attacks cotton and may become a serious 

 pest. 



The tree crickets differ greatly in appearance from the field and 

 mole crickets, being slender, greenish white and only about half to three- 

 quarters of an inch in length (Fig. 71). They occur on trees and bushes 

 and attract attention from July till .frost by their shrill, steadily repeated 

 note or song, beginning as it grows dark and continued through the 

 night, the rapidity of the note being so closely related to the temperature 

 that by timing the number of repetitions per minute a close approxima- 

 tion to the thermometer reading can be obtained. 



The tree crickets are rather serious pests as during the fall the females 

 make long rows of punctures in the twigs of trees and in berry canes 

 (Fig. 72), laying their eggs in these punctures which usually are nearly 

 as deep as the diameter of the twig or cane (Fig. 73). The general 

 result is the drying and splitting open of the portion of the plant attacked, 

 causing its death, besides providing an opportunity for the spores of 

 fungous diseases to enter and attack the plant. Control of these insects 

 is at present limited to cutting off and destroying the injured parts of the 

 plant, with their contained eggs, before these hatch in the spring. 



A few species of crickets live a semiparasitic life in ants' nests and in 

 consequence are so much modified as to show little resemblance to the 

 common forms. 



