11 



the eggs of the injurious species, sometimes on the larva, some- 

 times on the pupa. Figure 14 iUustrates the larva of one of the 

 grapevine moths covered with cocoons of a (j^rasite. Figure 15 

 shows the adult form of the parasite, both natural size and enlarged. 



Figure 14. Figure 15. 



Figure 16, from Packard, shows a fly which is beneficial. It is 



known as a Tachina fly. These flies are parasitic in caterpillars 

 and other insects. They lay their eggs on the caterpillar, and then 

 hatching, the maggots or larvae, destroy their nest. I once obtained 

 thirty-nine of these flies from the cocoon of a single Cecropia, and 

 many a collector has been disappointed in trying to obtain a speci- 

 men from the cocoon when, instead of the expected moth, he only 

 secured a small swarm of these hairy flies. 



Figure 16. 



Tachina Fly and Larva. 



