308 Observations on Insects fifFcctbifj the Timiij) Croj>s. 



the butterfly bursts the back of the chrysalis, crawls out, and, 

 holtling by some object so that the little wings hang clown, the 

 fluids descend into them, they rapidly expand, and in the course of 

 half an hour have attained their full size ; they are, however, still 

 flaccid, and require some time to dry and become adapted to flight. 



The caterpillars of the White Cabbage-Butterfly greatly injured 

 some Swedish turnips the end of last September, and no doubt 

 frequently assist in reducing the foliage very considerably ; but it 

 is when the turnips, &c., are in seed that they are most to be 

 feared. In July of the same year I received some of the cater- 

 pillars from Mr. C. Parsons, of Southchurch, Essex, who in- 

 formed me that they were then committing extensive ravages on 

 the white-mustard crops in parts of that neighbourhood, by eat- 

 ing off all the pods, and leaving the stalks bare, as shown in the 

 stem, fig. 9. They commenced at the point of the pod, and con- 

 tinued eating until it was demolished, even to the base of the foot- 

 stalk. '' Had they attacked the crop," says Mr. Parsons, '' at an 

 earlier period of the season, the consequences would have been 

 very serious indeed. Mustard- seed, both white and brown 

 (Sinapis alba nnd viyra), is subject to the attacks of a small black 

 larva, which I have not seen this year ; but the damage done by 

 the caterpillars I have sent has never been noticed in this neigh- 

 bourhood." 



I placed some of these larvae upon radishes and turnips in 

 seed, the green pods of which they were equally fond of, and ate, 

 as above stated. They grew most rapidly during the few hot dry- 

 days we had near the middle of September, 1841, resting lengthways 

 upon the naked stalks, after having cleared off all the seed ves- 

 sels (fig. 7) : on the 20th they appeared healthy, but inclining 

 rather to a yellow colour : it rained during the night, and, on look- 

 ing at them in the afternoon of the following day, I saw they had 

 removed to a leaf, toAvhichthey stuck by four of their hinder legs, 

 and to my surprise they were of a dirty colour, and rotten, the 

 skins being lax, and lying just as the wind blew them about. I 

 found they only contained some cream-coloured fluid, a portion of 

 which was scattered upon the leaves. From this fact it may be 

 inferred that wet is sometimes very destructive to them, probably 

 during hot weather only ; for after the heavy rains w hich fell the 

 end of September and in October, I was astonished to see the cab- 

 bages in the cottage-gardens in Suffolk with multitudes of these 

 caterpillars half and lull grown, which had injured the crops so 

 extensively, that not a leaf had escaped. It is scarcely credible 

 that the labouring classes should thus suffer their crops to be 

 spoiled, and their labour to be lost, when a little hand-picking 

 every evening would soon relieve their gardens from these un- 

 welcome visitors ; but so it is. 



