THE SPRINGTAILS AND FISHMOTHS 



(Order Thysanura.) 



The insects of this order are usually of very small size, and 

 are wingless and have practically no metamorphoses. They com- 

 prise the little insects known as springtails, bristletails, fishmoths 

 or slickers. They have three pairs of legs, the mouth-parts, often 

 hidden, are formed for biting, and the skin is delicate. The order 

 is supposed to comprise the most generalized or simplest forms 

 of insect life and although there is some reason for considering 

 that they are degenerate insects the consensus of opinion is that 

 they are living representations of primordial insects. Some of 

 them possess a very remarkable leaping arrangement in the shape 

 of a spring-like process on the under side of the abdomen, which 

 enables them to jump in an extraordinary way, some of them 

 have long abdominal appendages or processes at the end of the 

 body, and still others have short leg-like processes on the under 

 surface of the abdomen. The order as at present understood 

 comprises two suborders, namely the Cinura and the Collembola. 

 Formerly some curious creatures belonging to the genus Scolo- 

 pendrella were considered as belonging to this order and were 

 placed in a suborder by themselves — the Symphyla — but it is 

 thought now that these little creatures are more closely related to 

 the Myriopoda than to the true Insecta. 



The two remaining suborders may be separated as follows : 



With bristle-like and many-jointed appendages or forceps at the 



end of the abdomen, which is composed often segments and 



does not possess a sucker on the ventral side 



Suborder Cinura. 



With a forked sucker on the under side of the first abdominal 

 segment, and the abdomen, which is composed of not more 

 than six segments, furnished with a spring-like apparatus 

 near the tip, or without appendages. ..Suborder Collembola. 



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