172 THE CANADIAN ENTOMOLOGIST. 



indispensable accompaniment of the disease, but is its originating cause 

 and the means by which it can be and is conveyed to other individuals of 

 the species. 



By placing healthy silk-worms in contact with those suffei-ing from the 

 disease, by sprinkling them with the dust of excreta derived from the 

 latter, or by moistening their food with an infusion of the fermented mul- 

 berry leaves upon which these had fed, he proved the possibility of con- 

 veying the disease from one subject to another. 



In pursuance of this, Prof. Forbes has witnessed instances of epidemic 

 disease in different species of insects, as for instance in the Chinch Bug 

 and the Yellow-necked Caterpillar, which disease was invariably dependent 

 upon some form of bacteria or micrococcus, possible of cultivation and 

 reproduction, and by means of which the disease can be indefinitely con- 

 veyed. These facts give rise to the suggestion that the specific micro- 

 coccus or bacteria causative of these fatal diseases may be used for the 

 infection and destruction of insect pests. 



Prof. Osborn called attention to the fact that he had noticed Bombus 

 pensylvanicus inhabiting a deserted wren's nest, situated under the roof of 

 a porch, and at least twelve feet from the ground, it being the first instance 

 he was aware of where they nested away from the surface of the ground. 



Mr. D. S. Kellicott had noticed the same or some allied species of 

 Bombus inhabiting a mouse's nest in the brace of a barn. 



Miss Murtfeldt had also seen them domiciled in a martin's nest. 



Dr. Hoy presented for inspection the larvae, pupte and imagines of 

 P/usiodonta compressipalpis. He had watched the insect through its 

 transformations and had noted that during its early larval stages its pre- 

 vailing color was a pea green varied with uniformly placed black spots, 

 which increased in number with each successive moult. Only during the 

 last stage of its larval life was the insect usually noticeable by other than 

 professional eyes ; since then its color was reddish brown ornamented 

 with creamy white. Menispermum Canadei/se was its usual food plant. 

 The cocoon was formed by first building two nearly parallel walls and 

 then uniting them at the top. Some larvse which jiad been displaced after 

 beginning to pupate, had apparently become exhausted, or their teeth had 

 become loosened in anticipation of their approaching new condition, and 

 they were willing to • accept bits of paper held to them on a pin, with 

 which they finished the cocoons already begun. The species in Racine 

 cannot be more than two-brooded. The larva; are not distinguishable 



