376 



THE GYPSY MOTH. 



The first two and perhaps the last are the most useful in 

 destroying the gypsy moth, and probably are far more 

 successfal than the Dipterous parasites, since the latter lay 

 their eggs on the outside of the caterpillars, and many of 

 them are thrown ofi" on the molted skin before they hatch ; 

 while the eggs of the Hymenopterous parasites are deposited 

 in the tissues beneath the skin. 



During the summer of 1895, Theronia melanocephala 

 (Plate 53, Fig. 6) was the most abundant of the Hymen- 

 opterous parasites, and in the larger colonies could be 

 seen on warm days flying about from tree to tree, almost 

 invariably alighting on the burlap bands, and even crawling 

 under them in its search for pupae. In Lexington, on one 

 occasion, one of these insects was seen to go from tree to 

 tree until it had examined seven burlaps. After searching 

 the burlaps, the trunk of the tree above and below was 

 inspected, the antennae all the time being kept in constant 

 motion. It has been reported that this parasite attacks 

 the caterpillar when about to pupate ; but in nearly all the 

 cases where its oviposition was observed this year, some 

 eight or ten, the insects attacked were in the pupal stage. 

 The point of attack was on the ventral surface, at the 

 lower margin of the wing-cases, next the abdominal seg- 

 ments. Here the chitinous integument is very thin, and " 

 ofiers the least resistance to the insertion of the ovipositor. 

 When a suitable pupa is found, the parasite, after selecting 

 the point for attack, curves the end of the abdomen beneath 

 the body between the legs, and inserts the ovipositor into the 

 pupa by a succession of movements, the whole operation 

 requiring about a minute and a half. When disturbed by 

 the writhing of the pupa or otherwise, the parasite with- 

 draws her ovipositor and later stings again.. Only one 

 parasite has been reared from each parasitized gypsy moth, 

 and therefore we may infer that but a single egg is deposited 

 in a pupa. Mr. C. E. Bailej^ captured a specimen of TJier- 

 onia melanocephala in the act of stinging a gypsy moth 

 pupa which already contained a Dipterous maggot. Un- 

 fortunately, the pupa was so crushed that it was impossible 

 to ascertain what the result would have been. 



On one occasion a wood pewee was seen to snap up one 



