1902 Entomology in Spring 109 



could not have been accomplished earlier, since there were 

 no succulent shoots on which the caterpillars, soon to 

 emerge from the egg- state, could subsist. But the bulk 

 of them are new-born from their chrysalides, which have 

 been of two sorts. One is helpless and often immovable ; 

 the other is capable, by the aid of lateral hooks and other 

 interesting appendages, of considerable locomotion. The 

 pupa of the Goat Moth, for instance, so destructive to our 

 well-grown timber by boring long galleries into its solid 

 wood, wriggles along its tunnel, from the deep interior 

 where it has passed the winter secure from frost and foes, 

 to the surface of the tree, whence it may often be seen 

 protruding some inches after the escape of the perfected 

 moth. 



The methods by which insects are now liberating them- 

 selves from the more or less dense cocoons which have pro- 

 tected them from the rigours of the elements and the attacks 

 of enemies during hibernation, is a wide and most fascinat- 

 ing study, rendered the more interesting since the efforts of 

 the captives are by no means always rewarded by success. 

 When the full-grown caterpillar changes to a chrysalis, the 

 skin of the former splits open, and the fully formed pupa is 

 at once revealed within, though soft and white. As already 

 mentioned, chrysalides are of two kinds, known as hemi- 

 and homo-metabolous. In the latter the pupa in no way 

 resembles the future insect, and the metamorphosis is com- 

 plete ; in the former all the organs are already visible, 

 though swathed in transparent sheaths. Homometabolous 

 pupae often construct no cocoon, since their own integument 

 is sufficiently stout, but the hemimetabolous are always 

 further incased in such an exterior covering. These latter, 

 which are mainly beetles and the bee tribe, are furnished 

 with stout teeth, with which, when spring is come, they are 

 enabled, after slipping off the sheathing, to gnaw through 

 the cocoon and so reach the wide, wide world of light, air, 

 and sunshine. But moths, which, though homometabolous, 

 very often spin cocoons, and sometimes very tough ones 

 too, have no teeth but only a proboscis for sucking liquids. 

 How, then, do they pierce this outer vallum ? 



Let us take, as example, the strangest case of all — that 



