igS AN INTRODUCTION TO ZOOLOGY. 



therefore much more active, and able to run with 

 rapidity. 



The CJdlognatha are distinguished by having (ex- 

 cept on a few anterior segments) two pairs of legs on 

 each segment, and the body is not so flat as in the 

 last order. These include the true millipedes, Jidns : 

 they live on roots. Some of them have small eyes 

 {ocelli) aggregated together. The larger English 

 species are considerably over an inch long; they are 

 dark in colour, and shiny. Julus pulchellus is a very 

 small one, destructive to bulbs and hothouse plants; 

 it is of a pale colour, and blind. The Glomeridce are 

 short forms, with only a few segments, which curiously 

 mimic the wood-lice in appearance. 



The true Insects are called Hexapoda, because they 

 have only three pairs of legs in the adult form. Be- 

 sides these they often have wings. Only the lower 

 forms are developed straight from the egg; they 

 are therefore called Inseeta ametabola, insects which 

 do not undergo change; the rest undergo meta- 

 morphoses, more or less complete in character. The 

 Insects receive their name (cut in parts) from the 

 fact that they are divided into two body-regions : the 

 thorax, which has appendages, the legs ; and the 

 abdomen, which has no legs. These are separated by 

 a very marked constriction ; both have the segments 

 completely fused. The head is separate from the 

 thorax, and has appendages for biting, etc. Ento- 

 mology, the study of insects, is derived from their 

 Greek name, which is the same in meaning as the 



