24 



AN INTRODUCTION TO ENTOMOLOGY 



and maxillulae (m) 

 of Scolopendrella 

 (After Hansen). 



32, 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 maxilla or labium (Fig. 

 3 2 , /) 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 

 consist each of five segments; the last segment 

 bears a pair of claws. Excepting the first two 

 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 

 P '~* _**?$>$ with the cerci of insects (Fig. 3 5 , c) . 



A striking peculiarity of the symphylids is that 



Fig. 34- A leg of ^ e y p OSSe ss only a single pair of tracheal tubes, 

 Scolopendrella; , . , . r i *. u ^ *t 



, 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 measuring 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 : pi g . 35 .__The caudal 



Scolopendre.la and Scutigerella. In the former the e nd * the bcd y , f 

 , P jn 111 Scolopendrella; I, 



posterior angles of the terga are produced and i e g ; 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 



The Myrientoniatids 



The members of this class are small arthropods in which the body is 

 elongate, as in the Thysanura, fusiform, pointed behind, and depressed; 

 it may be greatly extended and retracted. The antenna and cerci are 



