THE EUROPEAN CORN BORER AND ITS CONTROL. 57 



The long period of fertility of the female moths in both generations of 

 the European corn borer is important because it results in larvae of several' 

 different instars being present in the same field, and often on the same 

 plant at the same time. This may be an important consideration in any 

 control measures that have for their object the destruction of the young 

 larvae before they enter the plant. 



The long period of fertility also increases the chances that gravid 

 females may start new infestations of the insect by being carried outside 

 of the infested area. 



PARASITES. 

 European Records of Parasites. 



European literature contains very few records of parasites bred from 

 the European corn borer in any of its stages. Most of the literature on 

 this species emphasizes the absence of any parasites. 



Robin and Laboulbene (11) mention the fact that one of their col- 

 leagues, M. Jules Fallon, reared many specimens of P. nubilalis (Botys) 

 from larvce to adults during several consecutive years prior to 1879, but 

 secured no parasites, either hjanenopterous or dipterous, from any stage 

 of the insect. 



Jablonowski (16) records breeding a parasite fly, Ceromasia interrupta 

 Rdi., from the larva of P. mibilalis. The author states that "the insect 

 is not much infested by parasites in Hungary." 



Kollar (6) mentions that some Ichneumonidae have been bred from the 

 insect. 



Records of Parasites in Massachusetts. 



No parasites were bred from the egg of the European corn borer during 

 the investigations in Massachusetts. 



Parasites of the Larva. 



In Massachusetts four different species of dipterous parasites belonging 

 to the Tachinidse have been bred from larvse of the borer. These Tachinids 

 were determined by Dr. J. M. Aldrich of the United States National 

 Museum as Masicera myoidea Desv., Exorista pyste Walk., Exorista 

 nigripalpis Tns., and Phorocera erecta Coq. No other parasites were 

 bred from P. nubilalis larvae. 



In each of the species noted above the parasite larva emerged from its 

 host larva just previous to normal pupation of the latter. All of these 

 records were secured from host larvse collected in the field and kept under 

 observation in cages. During the progress of dissecting infested plants 

 in the field, occasional parasitic dipterous larvae and puparia were found 

 in the tunnels of P. nubilalis. In these instances it was not possible to 

 state definitely whether the parasite had emerged from P. nubilalis, or 

 from some other larva which had wandered into the P. nubilalis tunnels. 



