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^E. 



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 FlG ( 

 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, Jdpyx, has been described. Jdpyx subterrd- 

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

 Mammoth Cave." 



Family II. CAMPODEID^:. This family resembles the preced- 



FIG. 59. Ventral 

 aspect of Ma- 

 chilis, showing 

 appendages. 



