PARASITISM OF GIPSY MOTH IN" AMERICA. 139 



larva had issued, and spun a cocoon identical in appearance with that 

 of the species from the tussock moth. This is the only known 

 instance of the parasitism of the gipsy moth by an American Apan- 

 teles, and it is believed that it resulted through the fact that the par- 

 asites were first attracted, and subsequently excited into oviposition, 

 by the tussock caterpillars. 



A considerable number of a minute black and yellow elachertine 

 secondary parasite was reared from this cocoon, so that the specific 

 identity of the Apanteles originally constructing it will forever 

 remain in doubt. 



Syntomosphyrum esurus Riley. 



In July, 1906, Mr. R. L. Webster, who was at that time associated 

 with the parasite laboratory, found a pupa of the brown-tail moth 

 from which he reared a number of Syntomosphyrum, probably 

 S. esurus Riley. On the same date, July 18, the pupa of a gipsy 

 moth was found to contain the early stages of a chalcidid parasite, 

 presumed to be the same as that reared in connection with the 

 brown-tail moth. 



At about the same time several chalcidids, apparently of Synto- 

 mosphyrum, were found ovipositing in pupae of the gipsy moth, but 

 in no instance was the oviposition successful, so far as the notes 

 indicate. 



Tachina mella Walk. 



In their report on the gipsy moth Forbush and Fernald speak of 

 having collected no less than 300 caterpillars of the gipsy moth 

 bearing Tachina eggs which were reared through in the laboratory. 

 The most of these produced moths and the remainder died. No 

 parasites were reared. 



In 1907 and subsequently large numbers of caterpillars have been 

 found in the open, bearing tachinid eggs, and many hundreds have 

 been kept under observation in confinement with results substan- 

 tially the same as those above mentioned. In one or two instances,, 

 however, the tachinids have completed their transformations and 

 in each instance the species was Tachina meUa. It is believed, there- 

 fore, that this is the species which deposits its eggs so freely and 

 injudiciously. 



The fact that effective parasitism failed to result was attributed by 

 Forbush and Fernald to the molting off of the eggs before they had 

 hatched, and this doubtless does occasionally happen. Mr. C. H. T. 

 Townsend reinvestigated the subject and came to the conclusion 

 that the explanation was to be found in the inability of the newly 

 hatched larvae to penetrate the tough integument of the caterpillars, 

 since he actually observed such failure in one instance, and found 



