27 



that it cannot always be detected ; its presence, however, may usually be traced by the 

 singularly marked cylindrical pellets of excrement on the ground, and the stripped leaf- 

 stalks of the plant. When fully grown the larva descends into the earth, and there makes 

 a chamber for itself in which to change to its pupa state. Fortunately the insect is not a 

 very common one, its numbers being kept in check by a small ichneumon-fly ; otherwise 

 from its size and voracity it would prove most destructive. Very rarely are more than a 

 few specimens seen in a tomato or potato patch. In the summer of 1878, however, as I 

 recorded in the Canadian Entomologist (vol. x., p. 218), it was so abundant that a 

 market-gardener who lives near me gathered four bushels of the caterpillars off an acre and 

 a quarter of tomatoes in one day ! That year some of the insects attained to the moth or 

 imago state in October, but generally the pupa remains quiescent in the ground till the 

 following season, and the moth appears in June or July. I have now in my possession a 

 living chrysalis of this insect that belonged to the abundant brood of 1878. It was given 

 to me by Mr. David Smart, of Port Hope, who found it, with a large number of others, 

 in his garden. He kept the chrysalids in a box of earth in his cellar all last year ; no 

 doubt the coolness prevented the development of the imago. He and I are now both 

 watching with much interest for the appearance of the moths from our specimens, as two 

 years in the pupa state is by no means a common occurrence. That the pupse are still 

 alive is shown by the readiness with which they move the segments of the abdomen when 

 handled or disturbed.* Notwithstanding the extraordinary abundance of the larvae in 

 1878, there were but few to be seen last year in this neighbourhood. 



An account of the "tomato worm" will hardly be complete without some leference 

 to the supposed poisonous character of the larva. Some ten years ago, when in charge of 

 the Entomological department of the Canada Farmer, I took the trouble to trace up some 

 of the stories then very common in the newspapers about cases of poisoning and death 

 from the effects of the bite or sting or venomous spittle of this insect ! The result of my 

 inquiries in many instances proved to be exceedingly amusing. In every case I found 

 that no one could give any information whatever as to even the name of the person who 

 was supposed to have died from the effects of this insect, nor could I obtain a single 

 authentic instance of injury from it. This was, of course, what was to be expected, as 

 the caterpillar is physically incapable of injuring anyone with its bite — much less with its 

 tail or horn, or imaginary sting. In all probability these stories have originated in the 

 fact that persons have been severely affected by getting some of the juices of the tomato 

 plant into an open cut or sore, and then ignorantly have attributed their trouble to the 

 venom of the ugly but innocent caterpillar. 



Migratory Insects. 



By G. J. Bowles, Montreal, P.Q. 



The migratory instinct, common to so many species of birds, and even of mammalia, 

 is also exhibited by many species of insects. In the case of birds and animals it has 

 mostly to do with variations of climate, or the necessity of suitably providing for the rais- 

 ing of their young ; in the case of insects the causes of migrations are not so evident, and 

 observation is required in order to decide the point, if, indeed, it can be decided at all. The 

 subject is still in obscurity, though the efforts of American Entomologists have thrown a 

 little light upon it with regard to some species. And it is of great interest, not only to 

 Entomologists, but also to tillers of the soil, as some of the insects which exhibit this 

 migratory instinct are among the most injurious to the crops of the farmer and fruit 

 grower. 



The Locust. 



Chief among the migratory insects stands the locust, considered as a group. On each 

 of the continents, both of the old and new worlds, some species of the locust tribe have 

 from time to time been notorious for this habit, not only on account of the countless 

 numbers in which they have appeared, but also on account of the terrible destruction they 



* The Moth emerged from the pupa referred to on the 27th of May, after being nearly two years in 

 that state. 



