204 INSECT TRANSFORMATION 



dwelling places of insect larvae are, as might be expected, 

 closely connected with the sources of their food supply, and 

 this is especially evident in the case of maggots and legless 

 grubs, creatures for the most part, of sluggish habit, which find 

 in some organic substance, whether plant or animal, living or 

 decaying, both shelter and food. 



The varying feeding habits of insect larvae furnish a wide 

 subject of inquiry to the student. It is during the larval 

 stages that an insect achieves its growth in so far as increase of 

 bulk is concerned, and among those insects which pass through 

 complete transformations with the accompaniment of a pupal 

 stage, a store of food material has to be accumulated to provide 

 for the rapid growth of all the imaginal buds both external 

 and internal which marks the close of the metamorphosis. 

 In many insects, such as the whole order of the mayflies 

 (Ephemeroptera), and certain families of Lepidoptera 

 (Hepialidae, Lasiocampidae, Bombycidae, Saturniidae, for 

 example) there is no feeding by the adult, whose only function 

 is breeding, and all the food on which the creature is dependent 

 for its entire life-activities must be taken by the larva. Hence 

 it may be seen how important is this question of how or what a 

 larva eats, and it may be understood how powerfully this factor 

 of feeding must have affected the course of insect transformation. 



A vast multitude of insect larvae feed directly on the tissues 

 of living plants. In illustration of their variety it may be well 

 to consider briefly the insect population of one or two common 

 and familiar trees. On the leaves of an apple-tree 1 may be 

 found feeding the caterpillars of many Lepidoptera such as 

 the bulky green larvae of the Eyed Hawk-moth (Smerinthus 

 ocellatus), the restless, conspicuous hairy " tussocks " of the 

 ' Vapourer ' (Orgyia antiqua), the brightly adorned cater- 

 pillars of the " Lackey " (Clisiocampa neustria), and the small 

 dark ones of an Ermine-moth (Hyponomeitta) living socially 

 on a mass of web spun by their common labour, besides the 

 most destructive of all, the green, pale-lined " loopers " of the 

 Winter-moth (Cheimatobia brnmata) and its allies. These feed 

 mostly on the foliage, but some of them also devour blossoms 

 which furnish a particularly attractive feeding-station for some 



1 F. V. Theobald : " The Insect and other Allied Pests of Orchard, Bush, 

 and Hothouse Fruits ". Wye, 1909. 



