CHILOPODA 473 



and the maxillae are leg-like; body with 11 segments with 13 pairs of 

 legs; ej'es present; no stink glands; no copulatory feet in the male; 

 anus in penultimate segment: 1 genus. 



PoLYXENUS Latreille. With characters given above: 1 species, 

 which cannot roll itself together. 



P. fasciculatus Say. Length 2.5 mm. ; color pale brown ; head broad, 

 partly covered with hairs, with small eyes, and short thick antennae; 

 feet white: under stones and bark; the southern states; Long Island; 

 not common. 



Order 2. CHILOPODA.* 



The centipeds (Fig. 734). Elongate and flattened myriapods with 

 one pair of legs on a segment, Scutigera forming an apparent exception; 

 number of leg-bearing segments varies from 

 15 {Lithohius, Scutigera) to 173 {Geophili- 

 dae) ; antennae long and at least 12-jointed ; 

 2 pairs of maxillae present, the first pair not 

 being united, the second being prominent 

 palp-like structures, the basal parts of which 

 are joined in the median line; a paired upper 

 lip in front of the mandibles; legs usually 

 long, those of each pair being widely sep- 

 arated from each other on the ventral sur- 

 face; the first pair modified to form a pair ^ro^f' ,^t^T!movof ml 

 of hook-like jaws called the maxillipeds, ^^^;f\^J^^t SL^illlVel; 

 which project forwards beneath the head and ^^^J^^* sSSite' ' ^' ^"^^^ ^'^^' ""^ 

 are prehensile organs, each being provided 



with a poison gland ; the broad bases of the maxillipeds are joined in the 

 middle line to form a lower lip; tracheae similar to those of insects, 

 consisting of branching and usually anastomosing trunks, the spiracles 

 being situated on the side of the body on certain of the segments; genital 

 glands open to the outside in the penultimate segment; the young animals 

 possess all their legs at birth in the Geophilidae and Scolopendridae, and 

 7 pairs in the Lithobiidae and Scutigeridae: about 800 species, which are 

 active animals feeding on live animals and killing their prey with the 

 poison of the maxillipeds ; certain of the tropical Scolopendridae can inflict 

 a wound which is dangerous to man ; 4 families. 



* See "The Chilopoda of California," by R. V. Chamberlain, Pomona Jour. Ent, 

 Vol. 4, 1912. "Notes on Geophiloidea from Iowa," etc., by same, Canad. Ent., Vol. 44, 

 1912, "The Geophiloidea of the Southeastern States," by same. Bull. Mus. Comp. 

 Zool., Vol. 54, 1912, "The North American Chilopods and Diplopods," by same, Ann. 

 Ent. Soc. Am., Vol. 5, 1912. 



