864 SIPHON A PTERA AND COLEOPTERA 



segments posteriorly. The head is in the bottom of the burrow 

 in the skin, and the posterior abdominal segments block the opening. 



The eggs are expelled through the opening in the skin, after which 

 the female jigger is expelled by ulceration. The egg develops into 

 a larva with thirteen segments. This larva spins a cocoon, inside 

 which is the pupa, which gives rise to the imago in about eight to 

 ten days. 



Pathogenicity. — ^This will be described later (Chapter XC VL), but 

 it may be mentioned that it includes irritation, pus formation, 



ulceration, and forma- 

 tion of a sore, which 

 may become infected 

 with bacteria, and 

 cause loss of a toe or 

 a leg, or even tetanus 

 may develop. 



Family Pulic;d^ 

 Stephens, 1829. 



Siphonaptera with 

 body compressed or 

 elongated, always 

 larger than in the 

 preceding family. 

 Head, in comparison 

 Fig. 4S7.—Ctenocephalus felis Bouche. to the rest of the 



This drawing shows the combs on the head and body, small; top 

 prothorax. round; venter pro- 



tected with hairs ; 



often no eyes. The antennal groove is at times covered by a chitinous 

 plate. The end segment of the antenna is either segmented or un- 

 segmented. Thorax wide; pronotum often with ctenidia. Abdo- 

 men never so swollen that the original form is lost. Female never 

 endoparasitic. 



There are three subfamilies : PulicincB Tiraboschi, TyplopsyllincB 

 Tiraboschi, Hystrichopsyllince Tiraboschi. 



Subfamily Pulicin^e. 



PuUcidse with eyes. 



The more important genera of the Pulicinae may be arranged as 

 follows (modified after Jordan and Rothschild) 



A. Ctenidia on prothorax and head — Ctenocephalus . 



B. Ctenidia on prothorax, and only two teeth on cheek at genal angle — 



Chiastopsylla. 



C. Ctenidia on prothorax only. 



I. Pygidium freely projecting behind — Pygiopsylla. 

 II. Pygidium not freely projecting behind. 



(1) Club of antenna completely segmented- — Ceratophyllus. 



(2) Club of antenna incompletely segmented — Hoptopsyllus. 



