SYMPHYLA. 



605 



The head * carries a pair of long multi-articulate antennae 

 and three pairs of jaws : these are one pair of 2- jointed mandibles ; 

 a pair of maxillae bearing a short palp and ending in two lobes ; 

 and a labium consisting of a median basal part carrying two pairs 

 of small lobes. In addition there is a hypopharynx, on each 



FIG. 363. ScMiger- 

 ella immaculata 

 (after Latzel). 



FIG. 364. Ventral view of hind i-nd of 

 body of a young Scttii'ierella irnmam- 

 lata (after Latzel). // Bp Eleventh 

 leg ; VB protrusible ventral sac ; 

 p cerci with spinning organ. 



side of which is articulated a mnxillula (Hansen, paraglossae of 

 Grassi). The maxillulae probably represent the appendages of a 

 segment, which is found in the embryo of some insects between the 

 mandibles and 1st maxillae, and is supposed to be homologous 

 with the segment of the 1st maxillae of Crustacea. Similar 

 structures appear to be present in Collembola and Thysanura. 

 In addition to these parts there is an upper lip. Eyes appear 

 to be absent, or represented at most by a pair of ocelli. The 

 legs of the first pair are placed on the segment following the head 

 and are 4-jointed (in some species reduced to wart-like protu- 

 berances), the posterior eleven pairs being 5-jointed and ending 

 in two claws. The legs of a pair are set tolerably far apart 

 from one another (except those of the first pair). Close to the 

 coxae (or on them, Schmidt) of the legs of the last ten pairs 

 and on their inner sides there arise small movable processes 

 called parapodia (Fig. 364) and just on the inner side of each of 



* The constitution of the head of the Symphyla corresponds with tlmt 

 jjiven in the column for Insects on p. 325. 



