78 



ZOOLOGY 



to a segment and only one pair of maxillae. P. huxleyi 

 occurs both in Europe and in the United States (vicinity 

 of Boston and Philadelphia). Scolopenclrella l is a small, 

 white species, having very large -antennae and a pair of 

 backward-directed stylets. The mouth parts are very much 

 like those of the lowest insects, so that Scolopenclrella 

 bridges the gap between myriapods and true insects. 



APPENDIX TO CHAPTER V 



KEY TO THE PRINCIPAL FAMILIES OF THE MYRIAPODA 



i. Not more than 1 pair of feet to the segment ; 

 much segmented antennae ; 2 pairs of maxillae 

 [Chilopoda]. 



1 1. With facetted eyes ; 8 dorsal plates ; long 

 legs . .... 



1. 2 . "No facetted eyes, but single or aggregated 



simple eyes ; 15 or more dorsal plates. 

 Ci. 15 pairs of legs ; antennae at least ^ as 

 long as body ; body usually with 

 more than 20 segments 



Ci. More than 21 pairs of legs. 



f?i. 21 to 23 pairs of legs ; antennae 

 more than 14-jointed 



d>. Never less than 30 pairs of legs ; 

 antennae 14-jointed . 



Most of the segments with 2 pairs of legs ; an- 

 tennae with 5 to 8 segments ; 1 pair of maxillae 

 [Diplopoda]. 



l>\. Anus in penultimate segment ; body covered 

 with bunches of hairs .... 



1 Diminutive of Scolopendra. 



Scutigeridce 



(Ex. Scutigera) 



Lithobiidce 



(Ex. Lithobius) 



Scolopemlridw 



(Ex. Scolopemlni) 



Greophilidce 



(Ex. Geophilus) 



Polyxenidce. 



