154 PIONEA STRAMENTALIS. 



of the little creatures lying in rows side by side most 

 contentedly, and where they afterwards began to feed, 

 and to spread themselves in small companies over the 

 surface, but showed no disposition to wander away 

 from the leaf; thus they continued all through their 

 subsequent stages unto the very end of their career 

 to be of exceptionally amiable disposition, never inter- 

 fering with one another when, as often happened, some 

 would be laid up to moult while their companions were 

 still by their side feeding in such a sociable manner 

 as to suggest the probability of their being in nature 

 more or less gregarious. 



Very soon I experimented with six individuals by 

 placing them on leaves of Sinapis arvensis, and they 

 contentedly throve on this food as long as it could be 

 supplied ; but after a time these plants seeded so rapidly 

 that good leaves w r ere difficult to obtain, and as they 

 would not eat the seed-pods of this or the other plant, 

 but only the leaves, I eventually, after they had 

 moulted, returned them to their former companions 

 on the Barbarea ; Mr. Jeffrey had also varied the food 

 of some of his larva? by giving them Gardamine 

 amara, and he found they took to it freely. The result 

 of these experiments tended to the belief that though 

 the Barbarea is at least one of their natural food- 

 plants, yet that there are other plants liked by them 

 quite as well to be found amongst the tribe of Cruci- 

 ferm. 



The larvae moulted thrice, first from the 8th to the 

 10th of August, a few rather later; the second moult 

 happened with most of them on the 17th and 18th, and 

 the third moult occurred with some on the 24th ; and 

 all had safely accomplished that operation by the 27th 

 of the month. 



By the 9th of September all were full-fed, and shut 

 up in cocoons of earth, more or less in small companies 

 partly clustered together, many attached to the leaves 

 lying on the surface of the ground, in which none had 

 gone to any great depth. 



