228 



THE CANADIAN SPORTSMAN AND NATURALIST. 



Where did they come from ? A. iris is not a 

 common insect at any time, even in its favor- 

 ite haunts. Evidently they were strangers — 

 emigrants — they had crossed the sea from 

 their far off home in Germany, to be knocked 

 to pieces in London streets — sic transit gloria 

 mundi. 



4. Holding over or retardation of develop- 

 ment is one of those curious phases of insect 

 economy which has never been satisfactorily 

 accounted for. It is a well known fact among 

 English Entomologists that the Death's-head 

 moth (Acheroiitia atropos) is very apt to 

 remain two or three years in the pupa state, 

 therefore they.subject them to heat in order to 

 hasten their development. But even with this 

 help, some of them will still remain in pupa 

 tor one or two years. At a meeting of the 

 Entomological Club of the. American Asso- 

 ciation for the Advancement of Science 1876, 

 " Canadian Entomologist," v. viii p.p. 182-183. 



"Br. Morris asked if any of the gentlemen present 

 who were in the habit of raising larvae, had made obser- 

 vations in reference to the length of time the develop- 

 ment of the. perfect insect may be retarded. He stated 

 that three or four years since he had placed a number of 

 cocoons of S. cynthia on a shelf in his house, and that 

 after lying there all that time, some of them had this 

 year produced the perfect insect. Dr. Hagen referred to 

 an instance related by' Kirby and Spence (7th Edit. p. 

 321.) where a beetle (Buprestis splendida) was ascer- 

 tained to have existed in the wood of a pine table more 

 than twenty years." 



At p. p. 138-139 vol. ix., Canadian Entomolo- 

 gist, J. A. Moffatt writes : — 



" On the 24th September, 1875, I took a great many 

 large caterpillars of a reddish buff colour, with a dark 

 dorsal stripe, feeding on the willow. They soon went 

 down to the soil and spun themselves up in hard brown 

 cocoons, when I put them away for the winter. In the 

 spring of 1870, I brought them to the heat, and after 

 waiting some time and nothing appearing, I opened one 

 of them and found the caterpillar alive and as fresb in 

 colour as when it first spun up. In this condition they 

 continued until the fall, when I again put them away for 

 the winter. In the spring of __ 1877, I again examined 

 them and found them fresh and" with signs of life, but as 

 the season advanced, I opened some of them and found 

 them dead, and the remainder having assumed a shriv- 

 elled look, I laid them aside as hopeless. On the 17th 

 June, my attention was attracted by a scratching noise, 

 which I found came from these cocoons, which were now 

 reduced in number to six. On lifting, I found one of 

 them rattling and shaking with great vigour ; I returned 

 it to the box and waited three days; when nothing 

 appearing, I broke it open and a fully developed fiy 

 walked out in a very feeble condition, its length was I 

 inch; expanse lj inch; head, thorax and legs black; 

 antenna? and feet yellow ; abdomen brown, A yellowish 

 spot between thorax and abdomen; wings light smoky." 



From the foregoing, it may be deduced that 

 although a certain number of larva may be 

 subject to the same conditions, yet that the 

 result will not be the same individually ; as 



seemingly each has its own constitution and 

 measure of vital impetus, and no external 

 conditions (short of accident or actual destruc- 

 tion) will cause divergence therefrom ; and in 

 this we see a wise provision of nature, as, if 

 all the brood of these large and conspicuous 

 insects were to emerge at one time, their 

 chances of extermination would be. much in- 

 creased. But by a portion holding over and 

 only a sufficient' number being developed to 

 continue the species, without becoming unduly 

 conspicuous, a reserve is maintained for any 

 eventuality. It is remarkable that this pecu 

 liar property is only possessed in a marked 

 degree by the Sphingida^ and Bombycidaj. 



5. Occasional visitants are those which by 

 force of winds are blown upon our shores. 

 Instance that magnificent insect (Chcerocampa 

 ncrii) which has been taken in England at 

 long intervals, and its larva at still longer; 

 but from the fact of its having been taken in 

 both the larva and imago states, it must rank 

 as a British insect. There is no doubt that it 

 flies across the channel, as it is always taken 

 on the south or south-east coast. As the 

 French variety of the common goldfinch, 

 (Fringilla carduelis) in the spring and fall, 

 flies across the channel to the same coast to 

 feed and returns on the same day, there can be 

 no reason why so large and strong winged an 

 insect as C. nerii should not accomplish the 

 same journey, especially when attracted by 

 light ; but it must always remain a rare insect ; 

 its natural food-plant (Nerium oleander) being 

 well nigh unattainable, although it will feed 

 on the vine. Having now brought this article 

 to a close so far as my data and space will 

 permit, I must leave it in the hands of others 

 to furnish their quota of information on this 

 abstruce subject; being a firm believer in the 

 Caxtonian aphorism — That every man of 

 sound brain, whom you meet., knows some- 

 thing worth knowing better than yourself. 



Richard Shield. 

 Montreal, April, 1883. 



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