242 FOREST ENTOMOLOGY. 



diversity in apparent structure. They are generally composed of a 

 head and thirteen divisions or segments of the body. Those feeding 

 on the surface of foliage have generally well -developed legs, and 

 clothed with hairs, while those feeding within the tissues of the 

 plant are either footless or with partially-developed legs and smooth 

 surface. 



In the pupce there is also great diversity as regards form and habit. 

 In some, all parts of the future perfect insect are visible, while others 

 are enclosed in a silky cocoon. Some bury themselves in the soil, 

 while others pass their pupal stage within the leaf or other portions 

 of the food-plant. From a structural and evolutionary point of view, 

 the complex changes taking place within the pupal stage of a Lepid- 

 opterous insect are most remarkable, and would require a long and 

 detailed study to thoroughly understand. 



The mouth of a Lepidopterous imago presents a great change from 

 the mouth of the larva, inasmuch as the one is adapted solely for 

 sipping and the other for biting and masticating its food. As regards 

 special structure, the mouth of the fully developed insect is somewhat 

 difficult to understand, but the principal feature is a tube or proboscis 

 which is rolled up when the creature is at rest, and protruded when it 

 wishes to sip nourishment, as may be readily seen by the collector 

 when the moth is enjoying his prepared banquet of "sugar." The 

 proboscis, and the exact mode in which it acts, present many sug- 

 gestive questions. Thus the length of the proboscis is adapted to 

 the needs of the creature, inasmuch as the essential food often lies 

 at the bottom of a floral vessel which could be reached in no other 

 way except through the medium of a long tube. On the other hand, 

 a short tube is often recognised on the mere surface-feeding moths, 

 and still further in many species the mouth is atrophied, and minute 

 anatomical investigation shows that the stomach is in a correlated 

 condition. 



With reference to classification, it is obviously unnecessary, having 

 regard to the few species selected as arboreal Lepidoptera, to give too 

 many details of the larger-sized sub-families. Students, however, as a 

 general rule, may divide the order into two principal sections viz., 

 .Macro-Lepidoptera and .Mzcro-Lepidoptera. The former deals with 

 the larger-sized species, and the latter with the smaller or very tiny 

 creatures. 



In the smaller-sized moths or J/zVro-Lepidoptera it is essential in 



