COMMON BRITISH INSECTS. 



This seems to be a simple matter enough ; but it 

 really is not so, the question being one which has 

 occupied systematic zoologists for many years, and 

 which is even now rather a dubious one in several 

 cases. The word insect is, as a rule, employed very 

 loosely by those who have not studied the subject. 

 Spiders, for example, are generally called insects, and 

 so are woodlice, centipedes, and a variety of other 

 creatures which have really no right whatever to the 

 title. We will therefore see what an insect really is. 



Insects are technically described as being ' articu- 

 lated animals, breathing by trachea, divided into three 

 distinct portions viz. the head, the thorax, and the 

 abdomen passing through a series of transformations, 

 and having in thz perfect or " winged" state six articu- 

 lated legs and two antenna? 



We will now take this description and examine it 

 in detail. The articulated animals are formed on a 

 totally different plan from the vertebrates, molluscs, 

 radiata, or other divisions of the animal kingdom. 

 Their bodies are formed of a series of more or less 

 flattened rings, within which are contained all the 

 muscles and vital apparatus. It will be seen that a vast 

 number of animals come within this definition, which 

 includes not only the insects, but the Crustacea, such as 

 the crabs, lobsters, shrimps, woodlice, and others ; the 

 Arachnida, such as the spiders, scorpions, and mites ; 

 the Myriapoda, such as the centipedes and millipedes ; 

 and the Annelida, of which the common worm is a 

 familiar example. It is necessary, therefore, to find 

 some mode of distinguishing the insects from all the 

 other articulates, and, after much trouble, systematic 



