THE BRITISH LICE (ANOPLURA) AND THEIR HOSTS 15 



3. Eyes lacking. Fam. H^matopinid^ . . .5 

 Eyes present, well pigmented. Occurring on man. Fam. 



Pediculim;. Subfam. Pediculin^e . . -4 



4. Legs all of same size . . . Genus Pediculus 

 Anterior legs much smaller than others. Genus Phthirius 



5. Legs and claws all practically of equal size 



Subfam. FLmatopinin,e. Genus Hcematopiiuts 



Anterior legs smaller and with slenderer claw than the 



posterior pair, at least. Subfam. LinognathiN;E . 6 



6. Abdomen with well developed pleural plates . . 9 

 Abdomen entirely without pleural plates . . 7 



7. Abdomen with more than one row of hairs or spines on 



each segment . . . Genus Linognathus 



Abdomen with but one row of hairs on each segment . 8 



8. Gonapods moderately long ; behind each gonapod a stout, 



fiat, spine-like process . . Genus Cervophthirius 



Gonapods very short ; no flat, spine-like process behind 



them . . . Genus Hcemodipsus (in part) 



9. Anterior pair of legs equal to middle pair, both pairs very 



small, posterior pair large and stout Genus Enderkinellus 



Anterior legs smaller than either middle or posterior legs, 



and with much smaller and more slender claw . 10 



10. Abdominal segments with but a single transverse row of 



spines . . . Genus Hcemodipsus (in part) 



Abdominal segments, at least in part, with two or more 



transverse rows of spines . . . .11 



11. Abdominal tergites and sternites with not more than two 



rows of hairs or spines . . Genus Polyplax 



Abdominal tergites and sternites in part with three rows of 



hairs or spines . . . Genus Hoplopkura 



Family PEDICULID^. 1 



Antennae five-segmented. Eyes present, distinctly pigmented. 

 Legs fitted for climbing, the tibiae with a thumb-like process opposing 

 the claw. No pretarsal sclerite between tibia and tarsus. Parasitic 

 upon man. 



Subfamily Pediculin/e. 

 Characters of the Family. 



1 It must be clearly understood that the diagnoses given in the following list 

 have been modified so as to apply to British forms only. 



