254 TKANSACTIONS OF THE LILLINOIS 



According to this author the little cocoons are bright yellow. I 

 have found this season, upon the cabbages where the worms had been at 

 work, similar little cocoons, except that instead of being bright yellow 

 they are of a creamy white ; but I have not yet seen the perfect insect. 



Mr. Provancher, of Quebec, was the first to call attention to another 

 parasitic fly, which belongs to the same group as and resembles the com- 

 mon house-fly. This is a species of Tachina, and the maggot which 

 resides in the body of the cabbage-worm, living on the fatty portions, is, 

 according to Dr. Packard, flattened and sub-cylindrical, with both ends 

 of it rounded much alike, the mouth parts partly aborted, there being 

 only two retractile horny mandibles by which the fatty portions of its 

 host are eaten. 



There are other Ichneumon-flies which I am inclined to think are at 

 least occasionally parasitic upon the worm, as I have noticed them fre- 

 quently about them and on the cabbages where the worms were at work — 

 one apparently a microgaster and another supposed to be a Pimpla. Some 

 fifty or sixty cabbages in my garden were devoted to the worms the past 

 season for the purpose of experimenting with them; on some the worms 

 were quite numerous up to November, now it is almost impossible to find 

 a chrysalis, while those bred in cases have long since passed into the pupa 

 state and most to the perfect insect. The question therefore arises, what 

 has become of the worms on the cabbages ? Have thfey been transformed 

 into butterflies by the warm weather ? or have they been destroyed by 

 parasites and other enemies? 



A few butterflies were seen as late as the first part of November, but 

 not after all the worms had disappeared. Dr. Fitch noticed a spider, 

 which he names the "Cabbage-spider" (^Theridion brassicce), feeding on 

 the young caterpillars. 



This is about one-fifth of an inch long, of a waxy, white color, with 

 two black parallel lines along the middle of the front part of the body; 

 the legs long and slender. 



He also mentions and describes another species, the " Underleaf- 

 spider" (^Theridion hypophyllum)., about the same size as the preceding, 

 with the front part of the body and thighs a bright cherry red; its globular 

 abdomen black and shining. 



We may add also as natural enemies insect-eating birds and domestic 

 fowls; the latter especially are efficient aids, as will be found by allowing 

 a hen or two with flocks of chickens the range of the cabbage-patch, a 

 plan I carried out in 1878, but neglected to do in 1879. 



Artificial Remedies. — Old Vincent Kollar, in his work on ''Injurious 

 Insects," says: 



The best way to destroy them is picking off and killing the caterpillars as well as 

 the pupae, as far as it is possible; the latter are found attached to adjacent trees, hedges 

 and walls. 



Curtis, in his ''Farm Insects," says: 



There are several methods of reducing their numbers and checking their increase ; 

 the best is to look in the winter for the chrysalids, which are concealed under the ledges 

 of walls, palings, doors, window sills, on bushes, in hedges, on the trunks of trees, etc., 



