ii6 The Ottawa Naturalist. [Aug-ust 



This outbreak, however, was terminated suddenly late in August 

 and in September by a bacterial disease of a very virulent nature. 

 (2) The Birch-tree Ske\eton\zer {Buccula^rix Canadensisella, Cham- 

 bers). This is a minute moth, the caterpillars of which sometimes 

 occur in vast numbers and attack the foliage of all kinds of 

 Birches. Last summer there was an excessive outbreak of this 

 insect, and Birches throughout the Province of Ontario were much 

 disfigured by having their leaves skeletonized by the tiny cater- 

 pillars. The insect is of considerable interest to the Entomologist, 

 from the peculiar habit of the caterpillars, unusual among larvae, 

 of spinning on the leaves small circular flat shelters called pseudo- 

 cocoons, inside of which they moult their skins. The true cocoons 

 are beautiful little brown objects of an entirely different appear- 

 ance, resembling a tiny clinker-buiU boat turned upside down. 

 When full-grown the caterpillars let themselves down to the 

 ground and, after wandering to some distance in search of a suitable 

 place to pass the winter, spin these elegant cocoons. The work 

 of construction is a most interesting one to watch; three-fourths of 

 the cocoon is spun from one end, the caterpillar then crawls inside 

 and closes up the other end. Sometimes many of these cocoons 

 may be found beneath a convenient slab of rock, at other times 

 they are spun on fallen leaves, or on stems of plants close to the 

 ground. 



Among the most interesting insects reared during the sum- 

 mer was a family of the minute hymenopterous parasite Bceus 

 niger, of which Mr. Harrington reared four males and 20 females 

 from a single cluster of spiders' eggs. This is one of the smallest 

 insects we have, and the females are wingless, while the exceed- 

 ingly rare males are winged. 



Some of our members have made collections of insects in 

 various parts of the Dominion. Mr. J. D. Evans has done good 

 work at Trenton, Ont. Mr. J. M. Macoun, Naturalist of the 

 International Boundary Commission, brought back some choice 

 specimens from the Cheam Mountains, in British Columbia, a 

 locality also visited by Dr. Fletcher with good results. 



Of equal value with the work done in working out the life 

 histories of rare insects is a great increase to our knowledge of the 

 preparatory stages of many of our common species, which has been 



