356 



THE ANIMAL PARASITES OF MAN 



3. Fam. Tarsonemidce. 



A family distinguished by complete sexual dimorphism, the species of 

 which are provided with tracheae ; the legs have five segments ; the ter- 

 minal segments of the front pair of legs of both sexes possess a claw ; 

 the terminal segment of the posterior pair of legs of the male likewise 

 has a claw. In the female this pair of legs, like the second and third 

 pairs of both sexes, is provided with two booklets and a sucking disc. 

 The cuticle of the body on the back is " annulated." 



Pediculoides ventricosus (Newport), 1850. 



Syn. : Heteropus ventricosus, Newport, 1850; Acarus tritici, Lagreze- 

 Fossot, 1851 ; Physogaster larvarum, Lichtenstein, 1868 ; Sphcsrogyna ven- 

 tricosa, Laboulbene and Megnin, 1885. 



Males are oval in shape, 0*12 mm. in length and O'o8 mm. in 

 breadth, flattened. There are six pairs of chitinous hairs on the 



FIG. 232. Pediculoides ventricosus. After Laboulbene and Megnin (enlarged) 

 a, male ; b, young female ; c, gravid female. 



dorsal surface and a lyre-shaped lamella on the posterior part. 

 The female in the non-gravid state is cylindrical in form, 0*2 mm. 

 in length, and 0*07 mm. in breadth ; when gravid the posterior 

 part of the body becomes enlarged into a ball, which may attain 

 1-5 mm. in size, as in the case of Pulex penetrans, and of the female 

 Termites. On emerging the young are already provided with four 

 pairs of legs and copulate soon after birth. 



