56 



AN INTRODUCTION TO ENTOMOLOGY. 



pendages at the caudal end of its body. This insect, on account of 

 the minute, shining scales with which its body is clothed, -is known 

 as the fish-moth. And it is the most familiar representative of the 

 sub-order Cinura. Other species occur beneath the bark of decay- 

 ing trees and in similar situations. The caudal end of the abdomen 

 is usually furnished with slender bristle-like appendages. These 

 suggest the popular name Bristle-tails applied to the sub-order as a 

 whole. 



The body consists of the head, three thoracic and ten well-marked 

 abdominal segments. The antennae are large, many-jointed, some- 

 times longer than the body, and generally tapering towards the end. 

 The most remarkable character presented by this 

 order is a series of sub-abdominal appendages. These 

 are well shown in Machilis (see Fig. 59). Similar ap- 

 pendages are attached to the coxae of the second and 

 third pairs of thoracic legs. These abdominal appen- 

 dages are regarded as rudimentary legs. We have 

 here, therefore, a condition approaching that exhibited 

 by Scolopendrella. 



The Cinura (Thysanura of Lubbock) is divided into 

 three families. These can be distinguished as follows: 



A. Body not clothed with scales. 



B. Caudal appendages unsegmented, 

 horny and pincer-like. 



I. jAPYGID-iE. 

 BB. Caudal appendages many-jointed 

 and thread-like. 



II. Campodeid^e. 

 A A. Body clothed with scales. 



III. Lepismid.e. 



Family I. JAPYGID^E. — The most obvious char- 

 acter of this family is presented by the caudal 

 appendages. These resemble those of earwigs, 

 being in the form of horny forceps. The body is 

 not clothed with scales; eyes are wanting. The F,G ^^^bbSf?*"' 

 palpi are short ; and the segments of the ab- 

 domen are of nearly equal width. The sub-abdominal appendages 

 are represented by groups of hairs. 



Only a single genus, /d/>yx, has been described. Jdpyx subtcrrd- 

 neus " is found under stones at the mouth of a small grotto near the 

 Mammoth Cave." 



Family II. CAMPODEID/E. — This family resembles the preced- 



Fig. 59— Ventral 

 aspect of Jlfa- 

 c/it/is, showing 

 appendages. 



