1906 ENTOMOLOGICAL SOCIETY. 



difficult matter to procure a sufficient quantity of material for study, that 

 is, of the larvae and pupae, during the different seasons of the year, and had 

 never been able to get a satisfactory supply. Dr. Fletcher has told us that 

 if the remedies prescribed, which are well known, were fully carried out, 

 the insect would be kept well under control ; he entirely agreed that these 

 methods are the most rational and successful for combatting the ravages of 

 the insect. Prevention by parasites has long been discussed and surprise 

 has been expressed that their influence for good has been practically nothing. 

 This failure, he believed, was largely due to the counter influence of second- 

 ary parasites which have an extended geographical range. He then read 

 the following paper : 



I 



PARASITISM OF CARPOCAPSA POMONELLA. 



By Dr. W. Brodie, Toronto. 



The all important problems of parasitism, as means for checking the in- 

 crease of plant eating insects, have for more than half a century been much 

 in entomological literature, and it seems that parasitism is recognized every- 

 where as the great power arranged by nature to check the rapid increase 

 of plant eating species. 



The parasitism of the Codling-moth has not been overlooked. Several 

 species of primary parasites have been detected and identified, and surprise is 

 ofcen expressed that their influence for good is so little, we may say inap- 

 preciable. Now there may be several reasons for this ; it may be the primary 

 parasites we know are not the species arranged by nature to check the over 

 increase of the Codling-moth. But one special reason I have detected is the 

 presence of a secondary parasite, namely, Dibrachys honcheanus . This in- 

 sect has a wide geographical range in Asia, Europe and North America, 

 and although one of the smallest insects, exercises an immense influence 

 in the world of insect life as a checking and balancing-up power. So far as 

 known to us, it is without doubt an injurious insect, as most secondary 

 parasites are. 



On Aug. 28, 1905, I received from Mr. W. A. Peer, Freeman P. 0., 

 a small box containing 18 C. pomonella larvae and pupae. On Aug. 29, 

 there emerged 2 moths, 1 primary parasite, PimpJa pteralis, and 12 second- 

 ary parasites, Dihrachys honcheanus. Sept. 20, 1905, a package from Stay- 

 ner gave from June 2-10, 1906, 17 moths and one primary parasite, a Pim- 

 pla. Sept. 25, 1905, a package from Prescott, gave in June, 1906, 4 moths 

 and 2 primary parasites, 1 Pimpla, 1 Ephialtes. I may say that I am in- 

 debted for iaentifications to Dr. Ashmead, of Washington, acknowledged 

 to be the highest authority on parasitic Hymenoptera in the world. 



During the many years in which I have been engaged in working out 

 some of the problems of parasitism, I have found the primary parasitism of 

 the Codling-moth to be about 0.5 per cent. No doubt it would be much 

 greater were it not for the presence of the secondary parasites. In a further 

 pursuance of the many interesting, practical and important problems pre- 

 sented, such as the life histories and relations of the primary and secondary 

 parasites known to infest the larvae and pupae of the Codling-moth, and the 

 relationships of these to allied species, preying abundantly on numerous 

 species of Tortricidae, more or less common in open woods and thickets 



