174 INSECT ARCHITECTURE. 



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 

 mirijiua), 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 lackey's encountered the brown -tails they mani- 

 fested no alarm or 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, ^ 



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 skillfully 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 



* See p. 115. t J. R. 



