CAUSES OF MIGRATION: FOOD-PLANTS. 251 



wild and cultivated. The uncongenial climate of the Temporary region 

 doubtless prompts the insect to get back to more congenial regions, and 

 we must allow a certain amount of instinctive guidance akin to that pos- 

 sessed by migratory birds. 



FOODPLANTS. 



" The Rocky Mountain Locust may be said to be almost omnivorous. 

 Scarcely anything comes amiss to the ravenous hosts when famished. 

 They will feed upon the dry bark of trees or the dry lint of seasoned 

 fence-planks ; and upon dry leaves, paper, cotton and woolen fabrics. 

 They have been seen literally covering the backs of sheep, eating the 

 wool 5 and whenever one of their own kind is weak or disabled from 

 whatsoever cause, they go for him or her with cannibalistic ferocity, 

 and soon finish the struggling and kicking unfortunate.^^ They do not 

 refuse even dead animals, but have been seen feasting on dead bats and 

 birds. Few things, therefore, come amiss to them. Yet whero food is 

 abundant they are fastidious and much prefer acid, bitter, or peppery 

 food to that which is sweet." 



It is quite evident, also, from the facts we have collected, that the 

 insects act somewhat differently during different years in this matter 

 of choice of food-plants, for at one time they will be particularly severe 

 on some plants that had been passed by on a previous occasion. While, 

 therefore, experience is often naturally conflicting as to their preferences 

 and dislikes, the following resume of onv notes made during the past 

 four years will prove interesting : 



" Vegetables and cereals are their main stay. Turnips, rutabagas, 

 carrots, cabbage, kohlrabi, and radishes are all devoured with avidity ; 

 beets and potatoes with less relish, though frequently nothing but a few 

 stalk-stubs of the latter are left, and sometimes the tubers in the ground 

 do not escape. Onions they are very partial to, seldom leaving anything 

 but the outer rind. Of leguminous plants the pods are preferred to the 

 leaves, which are often i)assed by. Cucurbitaceous plants also suffer 

 most in the fruit. In the matter of tobacco their tastes are cultivated, 

 and they seem to relish an old quid or an old cigar more than the green 

 leaf. Tomatoes and sweet potatoes are not touched so long as other 

 food is accessible.'^ Mr. W. D. Donaldson, of Headsville, Tex., reports 

 a case in Limestone County, in that State, where the insects, in 1870, 

 were noticed to fall greedily upon a tobacco- patch of second growth, 

 and where they died soon after eating thereof. Other cases of the in- 

 jurious effect of tobacco upon them have been reported to us. It is 

 more than probable, however, that the insects would also have been 

 found to die elsewhere with further investigation, and that the death 

 of those in tobacco-patches resulted from other and more natural causes, 



^ Mr. D. T. Ward, of Irvina", Kans., eTeu assured us that he hatched three eojg-massesin February, 

 1877, aud that the young, which were kept in a bottle, fed upon one another until one of them became 

 winged. Onr own experience and experiments forbid belief in the truth of the statement, and wecito 

 it more to show how unreliable statements often become from a tendency to exaggeration. 



