8 THE CANADIAN ENTOMOLOGIST. 



In a collection of over roo galls, made about 12 miles east of the 

 city, from Sept. 1 to Sept. 15. 18S6, all the producers had emerged. 

 About 50% of the galls were parasitized, principally by G. gelechiae. 

 These, from 12 to 20 pairs from each infested gall, emerged during the last 

 week of September and the first week of October, 1S86. I find they 

 always leave the gall before winter. 



The P'nnplas began to emerge April 17, 1SS7. Seven pupae of an 

 Ichntumonoid were put in a separate jar, the imagoes began to emerge June 

 1, 18S7, but from one pupa there emerged an Or my r us, proving this 

 Ormyrus to be a secondary. 



From a collection of .galls made at Grimsby in May, 1892, the 

 growth of 1891, Pimplas emerged from June 1 to June 13, 1892. At this 

 last date galls of the year were fully grown. 



The moths pass the winter in some secure dry place, such as under 

 the bark of dead trees. I have kept specimens over winter several times 

 in my cellar, the following season they pair and oviposit on Solidago 

 plants when they are less than half-grown. 



The most common primary parasites are the "Inflating Chalcid," of 

 Riley ; Copidosomagelechio, of Howard, which emerges the same season, 

 usually in September ; it is not likely they find another host of the season, 

 but hibernate in the imago form. The inflated skin of the producer larva 

 is like a sack full of the larvee and scmipupae of the parasite. 



Two common parasites are Pimpla inquisitor and Pimp la pier alt's, 

 the last not quite as common ; and that ubiquitous scourge of leaf-eating 

 insects, Cryptus exirematis, not rare. These, with an fc/ineumonid, not 

 yet identified, are the primary parasites I have had from this gall. 



The only secondary parasite which I have found in this gall-life 

 system is that world-wide regulator of life-relationship in the insect world, 

 Dibrachys boucheanus. 



I found this secondary in the galls collected near Grimsby and in a 

 lot collected near Prescott. The occurrence of this secondary in the 

 Solidago gall may be of much economic importance, for, as Dibrachys 

 is a check on the primary parasitism of the codling moth, the co-host 

 relationship may be favourable to the secondary or otherwise. 



The agency of parasitism is powerful, and should not be discounted 

 by economic entomologists, and while destroying the injurious, it is wise 

 to utilize the safeguards which nature has provided. It is, unfortunately, 

 true that we know of but few cases in which plant-eating species can be 

 successfully combated while in the imago form. 



