THE TWO-WINGED PARASITES 193 



asite remains with its host, working its way through the 

 skin to the inside and there remaining until it reaches its 

 full development into the adult fly, at the expense of the 

 life of its caterpillar victim. 



OBSERVATIONS FOR PUPILS 



1 . Examine carefully the caterpillars you find to see if any of them 

 show Tachinid eggs. 



2. Watch for the development of Tachina Flies from the caterpillars 

 you rear in breeding cages. 



Read : 



The Value of Insect Parasitism to the American Farmer, Yearbook Reprint 

 447. The Relations between Birds and Insects, Yearbook Reprint 486. 



