110 



SECOND ANNUAL REPORT OF 



ingin the middle, he suspected would not develop into a butterfly, says 

 of this parasite that he afterwards found a cocoon [pupa?] by its side 

 which was smooth blackish and oblong, and so large that he could 

 scarcely believe it had escaped from the chrysalis, which Was, how- 

 ever, now pierced, in the middle and empty. M. Provancher goes on 

 to say: "Ten days afterwards, we perceived one morning that the co- 

 uoon was open at one end, and. there was buzzing about in the vial a 

 fly, which we recognized as belonging to the genus Sar cop hay a [fiesh< 

 flies], the larvae of which are known to develop in meat. Here then, 

 we exclaimed, when we saw this fly, is an enemy of the Rape Butter- 

 fly. But unfortunately the flesh-flies feed indiscriminately on almost 

 any kind of flesh, and never being very numerous, cannot become 

 very redoubtable enemies of this butterfly." 



With all due respect to my friend Provancher, I incline to believe 

 that he has mistaken a lachinafty which is a true parasite, for a flesh- 

 fly (Sarcophaga) which is only a scavenger. And if this be so, his 

 reasoning falls to the ground, for, as we may see in the Army-worm 

 article in this Report, there are no more efficient checks to the in- 

 crease of injurious insects than these same Tacliina flies. 



THE CABBAGE PLUSIA— Plusia brassica, N. Sp. 

 (Lepidoptera, Plusidas.) 



This is the next most com 

 if rtf0^ mon insect which attacks the 



>"*'-'' -\\r' Cabbage with us, and curiously 



enough it has never yet been 

 ' described It is a moth, and 



not a butterfly, and flies by 

 night instead of by day. In 

 1 the months of August and Sep- 

 tember the larva (Fig. 81, a) 

 may be found quite abundant 

 on this plant, gnawing large, 

 bcirregular holes in the leaves. 

 It is a pale green translucent 

 Worm, marked longitudinally 

 with still paler more opaque lines, and like all the known larvae of 

 the family to which it belongs, it has but two pair of abdominal pro- 

 legs, the two anterior segments which are usually furnished with such 

 legs in ordinary caterpillars, not having the slightest trace of any. 

 Consequently they have to loop the body in marching, as represented 

 in the figure, and are true "Span-worms." Their bodies are very 

 soft and tender, and as they live exposed on the outside of the plants, 

 and often rest motionless, with the body arched, for hours at a time, 

 they are espied and devoured by many of their enemies, such as 

 birds, toads, etc. They are also subject to the attacks of at least two 

 parasites and die very often from disease, especially in wet weather*. 



