24 AN INTRODUCTION TO ENTOMOLOGY 



2,2, mx) resemble in a striking degree the maxillae of insects, consisting 

 of a long stipes, (5), which bears a minute palpus, {p), and an outer 

 and inner lobe ; the second maxillce or labium (Fig. 

 32,/) also resembles the corresponding part of the 

 more generalized insects, being composed of a pair 

 of united gnathites. 



The legs of the first pair are reduced in size and 

 in the number of their segments. The other legs ^^pophl'i^i^^^ ^h) 

 consist each of five segments; the last segment andmaxillulaeCm) 

 bears a pair of claws. Excepting the first two (Iftt/'filntent 

 pairs of legs, each leg bears on its proximal seg- 

 ment a slender cylindrical process, the parapodium (Fig. 34, p). 

 These parapodia appear to correspond with the styli of the 

 Thysanura. 



At the caudal end of the body there is a pair of 

 appendages, which are believed to be homologous 

 / '■"^^^^rfH^ with the cerci of insects (Fig. 35, c). 



A striking peculiarity of the symphylids is that 



Fig- 34-— A ieg of ^-j^gy possess only a single pair of tracheal tubes, 

 Scolopendrella; ,., , . ff, . ^ . 



/>, parapodium. which Open by a pair of spiracles, situated in the 



head beneath the insertion of the antennae. 



The members of this class are of small size, the 

 larger ones measiuing about one-fourth inch in 

 length. They live in earth under stones and decay- 

 ing wood, and in other damp situations. Imma- 

 ture individuals possess fewer body-segments 

 and legs than do adults. 



Less than thirty species have been described; 

 but doubtless many more remain to be discovered. 



The known species are classed in two genera : pig. j^.—The caudal 

 Scolopendrella and Scutigerella. In the former the ^nd of the body of 



, . ^ r j_, j_ 1 -1 •, Scolopendrella; I, 



posterior angles of the terga are produced and leg; c, cercus (After 

 angular; while in the latter they are rounded. Latzel). 



A monograph of the Symphyla has been published by Hansen ('03). 



Class MYRIENTOMATA 



Professor Comstock, in the former editions of this book, gave this 

 group of arthropods the rank of a class, coordinate with the other 

 classes of the Arthropoda. 



The position and rank of these animals were uncertain at the 

 time the Introduction was written. Indeed, the affinities of the 



