34:8 Canadian Butterflies. 



below the McTavish house, fifty or sixty of these beautiful insects 

 could be counted at once, regaling themselves on the flower of 

 the thistles growing in that locality. In one small yard in the 

 city about twenty of the chrysalides were observed attached to 

 the fences and projections of the roof of the shed. There were a 

 few thistles growing in the yard, and these were much frequented 

 by the caterpillars. The larva, chrysalis, and imago could be all 

 well observed at the same time. A caterpillar was taken into the 

 house on the 19th of September, and put in a box covered with a 

 piece of gauze, and placed upright so as to afford it a chance of 

 suspending itself. It immediately crawled to the top of the box, 

 and, in about half an hour more commenced to spin a quantity of 

 fine white silk from its mouth. The next morning it was found 

 suspended in the usual position, with the head downwards. 

 It remained in this position two days, apparently becoming 

 smaller and shrivelling up. During the third night it was trans- 

 formed into a chrysalis, in which condition it remained until the 

 13 th of October, when the butterfly was produced. 



Another, which suspended itself to a window-sash, on the 13th 

 of September, had entered into the chrysalis state sometime be- 

 tween that date and the 16th. On the 11th of October the 

 butterfly appeared. A chrysalis was taken from the fence, on the 

 lYth of September, and brought into the house produced a but- 

 terfly on the 2nd of Oct., the time observed being 17 davs. How 1 

 long it had been in the chrysalis state, previously, is not known. 

 At this time of the year, therefore, this species remains in the 

 chrysalis state from three weeks to one month. 



This butterfly is one of the most interesting of all the Lepidop- 

 tera, on account of its very extensive geographical range, it being 

 common in North America, New South Wales, Java, Africa, 

 Brazil, and Great Britain. Its appearance appears to be some- 

 what irregular. Thus Westwood states : — " This is one of those 

 species of butterflies remarkable for the irregularity of its appear- 

 ance ; in some years occurring plentifully, even in the neighbor- 

 hood of London, after which it will disappear for several years. 

 Indeed, instances are on record in which, owing to the vast num- 

 bers, migration has become necessary ; and in the " Ann ales des 

 Sciences Naturelles," for 1828, an account is given of an extraor- 

 dinary swarm which was observed in the preceding May, in one 

 of the cantons of Switzerland, the number of which was so pro- 

 digious, that they occupied several hours in passing over the place 



