194 Insect Architecture. 



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 manifested no alarm nor uneasiness, but passed over 

 the backs of one another, as if they had made only a portion 

 of the branch. In none of their operations did they seem 

 to be subject to any discipline, each individual 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. B.) 



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 themselves 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 concealment, however, though it appear to be 

 cunningly contrived and skilfully executed, is not always 

 successful, 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 ichneumon, aware it should seem of the very 

 spot where the chrysalis lay within this leaf, was seen boring 

 through it with her ovipositor, and introducing her eggs 

 through the punctures thus made into the body of the 

 dormant insect. We allowed her to lay all her eggs, about 

 six in number, and then put the leaf under an inverted glass. 

 In a few days the eggs of the cuckoo-fly were hatched, the 

 grubs devoured the lilac chrysalis, and finally changed into 

 pupae in a case of yellow silk, and into perfect insects like 

 their parents. (J. K.) 



* See p. 100. 



