Vol. VI] FERRIS— AN OPLURA 133 



can region. It is certainly not unsafe to estimate that the 

 number of known species is not more than one-fifth of those 

 that actually exist. 



KEY 

 To Families, Subfamilies and Genera of Anoplura. 



1 — Body thickly beset with more or less short, stout spines, 

 or with spines and scales. Occurring exclusively on 



marine mammals. Family Echinophthiriid^: 2 



Body with spines or hairs always in definite rows, 

 never with scales. Occurring exclusively on land mam- 

 mals 4 



2 — Thorax and abdomen bearing delicate scales. Antennae 

 four- or five-segmented. Subfamily Antarctophthi- 



RIIN.E 3 



Thorax and abdomen without scales. Antennse four- 

 segmented. 

 Subfamily Echinophthiriin^e . . Genus Echinophthirius 



3 — Antennse four-segmented Genus Lepidophthirus 



Antennae five-segmented Genus Antarctophthirus 



4 — Head tubularly produced anteriorly; tibiae without a 

 thumb-like process opposing the claw. Family HyEMA- 

 tomyzim:. One genus, Hcematomyzus. occuring on 

 elephants. 



Head not so produced; tibiae with thumb-like proc- 

 ess opposing the claw 5 



5 — Eyes lacking. Family H^matopinid^: 9 



Eyes present, well pigmented. Occurring on man, apes 

 and monkeys. Family Pediculid^e . 6 



6 — Antennae distinctly five-segmented, abdomen without 



pleural plates. Subfamily Pediculin^e 8 



Antennae three-segmented or obscurely five-seg- 

 mented, abdomen with pleural plates. Subfamily Pedi- 

 CININ.E 7 



7 — Legs all with slender, pointed claws, abdomen with 



three pairs of pleural plates Genus Pedicinus 



Anterior legs with slenderer claw than the others, 



abdomen with two pairs of pleural plates 



Genus Phthir pedicinus 



