PULICID^. 



389 



pressed. There arc four long hairs on the side of each ring, 

 becoming longer towards the end of the abdomen, where they 

 are longer than the body is thick. The terminal segment of 

 the body is considerably^ smaller than the one preceding it, and 

 has two long spines arising from the tergal part of the ring ; 

 these spines seem to assist the larva in moving through the 

 haii-s and dust in which it lives. The well developed head is 

 rounded, conical, narrower than the prothoracic ring, pale 

 honey yellow, and with long three-joiuted antennae. 



Mr. Emertou, Avho made the drawings here given, informs 

 me that the larva.^, Avhen fifteen da3-s old, did not differ from 

 those freshly hatched. I have been unable to discover that it 

 moults. Westwood states that "when fully grown, which 

 occurs in summer in about twelve days, the larvae enclose 

 themselves in a 

 small cocoon of 

 silk. Rosel, how- 

 ever, observed 

 that some of the 



-=^^^ T 11 11-111 w~\f') 71 y c/'^iv'' 



larvae underwent -'^-. \ \ 1 - -Ipj^ n I -M ^ i^^^ 

 their transforma- '^^zS\''^V-\<.y^x^^r(f^'yi/j 41^^^^* 

 tions Av i t h o u t 

 forming any co- 

 coon." "The pa- 

 pa is quite inac- 

 tive, Avith the legs 

 enclosed in separate cases. The period of the duration of 

 the pupa state A'aries from eleven to sixteen da^s." Our 

 specimens Avere hatched early in October, and they probably 

 pass the Aviuter before changing, as "VVestAvood states that 

 they pass the Avinter in the larva state. The species here rcj)- 

 resented (Fig. 310, 6, maxillfe, and their palpi, a ; f?, the man- 

 dibles, Avhich are minutely serrated; c, labial palpi, the labium 

 not being shown in the figure) was found on the person of a 

 man, though it seems to ditt'er specifically from "Westwood's 

 figure of P. irritans Linn., the human flea ; other species live 

 on the dog, cat, squirrel, and other quadrupeds and various 

 birds. The antennae are concealed in a small cavity situated 

 behind the simple eyes and are four-jointed; in P. musculi 



