THE CANADIAN ENTOMOLOGIST. 77 



blackish dots more numerous on some specimens than on others. The 

 hind wings are sometimes paler than the fore wings, and at other times 

 tinged with orange red, while in other specimens we have observed that 

 the under surface of the fore wings assumed a dull rosy hue. The body 

 is a little deeper and richer in colour than the wings, and the abdomen is 

 ornamented with longitudinal rows of black dots ; on the upper surface 

 there is a row down the middle of the back, and one on each side, and 

 on the under surface there are sometimes two additional rows of smaller 

 dots. 



Although this insect is so common and well known in its larval con- 

 dition, it is not often seen en the wing. It flies at night, and being seldom 

 attracted by lights, it rarely finds its way into our houses. It is also pro- 

 bably subject to the attacks of ichneumons, which destroy some of the 

 caterpillars before they reach maturity. 



ON THE GEOGRAPHICAL DISTRIBUTION OF SOME GENERA 



OF CANADIAN INSECTS. 



EY FRANCIS WALKER, LONDON, ENGLAND. 



Before leaving the Canadian Chahidice, in hope of returning to them 

 when many more genera are discovered in Canada, I will mention Megas- 

 tigmus, which very probably occurs there ; it is a genus of Torymidcc^ and, 

 in some respects, connects that family with the Eurytomidcz, and is next to 

 the latter in the interest with which it may be regarded in case there is a 

 foundation for the report lately published concerning the seed-eating 

 habits of the species which represent it in California. But this does not 

 seem probable, as it is certainly carnivorous in Europe, where two species 

 exceed the others in beauty and are especially conspicuous, the great M* 

 gigartieus that maintains itself on the Cynips of a one-chambered gall in 

 the Mediterranean region, and M. dorsalis that, with various other species, 

 lives on the substance of the Cy?iips of the many-chambered Oak Apple 

 of North Europe. I have seen other species near London and in the 

 Alpine vallies of Switzerland, and they are attractive on account of their 

 comparative rarity, though their economy is but little known. The natural 

 history of the Australian species may be unknown for some time to come, 

 and I hope that its discovery will be preceded by attention to the 

 Canadian galls and to their parasitic inhabitants. 



