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CIRCULAR 3 4 6. U. S. DEPARTMENT OF AGRICULTURE 



northern regions, and has large red eyes. This parasite is known 

 to attack the eggs of more than 150 species of insects, including 

 those of leaf hoppers, sawflies. butterflies, and moths. 



The female Trichogramma wanders about upon the foliage in 

 search of eggs which she may attack. When these are found, she 

 climbs upon each one in turn, inserts the sting through the shell, and 



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Figure 11.- — T rich on ram ma mlnutum, a parasite of insect eggs: A. A female stinging 

 a moth egg and placing its own egg within it : B, a cluster of eggs, of which about 

 half have been parasitized and show the Trichogramma emergence holes. A, X 35. 



deposits an egg within it. The development of the larva is very 

 rapid under summer conditions, and the entire life cycle may be 

 completed in 1 week. It is thus seen that an exceedingly rapid in- 

 crease in numbers is possible. During the summer and early fall 

 months more than 90 percent of the eggs of many species of insects 

 may be destroyed by this parasite, and consequently it plays an im- 

 portant part in holding various pests in check. 



