174 INSECT AKCHITKCTUltK. 



genus. The experiment which we tried was to con- 

 fine two broods of different species to the same branch 

 by placing it in a glass of water to prevent their 

 escape. The caterpillars which we experimented on 

 were several broods of the brown-tail moth (Porthesia 

 auriflua), and the lackey (Clisiocampa neustria). 

 These we found to work with as much industry and 

 harmony in constructing the common tent as if they 

 had been at liberty on their native trees ; and when 

 the lackeys encountered the brown-tails they mani- 

 fested no alarm nor uneasiness, but passed over the 

 backs of one another as if they had made only a por- 

 tion of the branch. In none of their operations did 

 they seem to be subject to any discipline, each indi- 

 vidual appearing to work, in perfecting the structure, 

 from individual instinct, in the same manner as was 

 remarked by M. Huber, in the case of the hive-bees*. 

 In making such experiments, it is obvious, that the 

 species of caterpillars experimented with must feed 

 upon the same sort of plant*j\ 



The design of the caterpillars in rolling up the 

 leaves is not only to conceal themselves from birds 

 and predatory insects, but also to protect them- 

 selves from the cuckoo-flies, which lie in wait in every 

 quarter to deposit their eggs in their bodies, that their 

 progeny may devour them. Their mode of conceal- 

 ment, however, though it appear to be cunningly 

 contrived and skilfully executed, is not always suc- 

 cessful, their enemies often discovering their hiding- 

 place. We happened to see a remarkable instance of 

 this last summer (1828), in the case of one of the 

 lilac caterpillars which had changed into a chrysalis 

 within the closely-folded leaf. A small cuckoo-fly, 

 aware, it should seem, of the very spot where the 

 chrysalis lay within the leaf, was seen boring through 



*Seep. 115. f J R. 



