276 
Hominoxious Arthropods 
dd. Eyes indistinct or wanting; pharynx long and slender, fulturae very 
slender and closely applied to the pharynx; proboscis very long. 
Several genera found upon various mammals. H;ematopinid.;e. 
cc. Body swollen; meso- and metathorax, and abdominal segments two to 
eight each with a pair of stigmata; eyes wanting; antennae four or 
five-segmented; body covered with stout spines. Three genera found 
upon marine mammals. Echinophthiriid^e 
aa. Legs fitted for walking or jumping; spiracles of abdomen usually ventral; 
beak segmented. 
b. Apex of head usually directed anteriorly; beak arising from its apex; sides 
of the face remote from the front coxae; first pair of wings when present 
thickened at base, with thinner margins.HETEROPTERA 
c. Front tarsi of one segment, spade-form (pakeformes); beak short, at 
most two-segmented; intermediate legs long, slender; posterior pair 
adapted for swimming.CoRixiDiE 
ec. Front tarsi rarely one-segmented, never spade-form; beak free, at least 
three-segmented, 
d. Pulvilli wanting. 
e. Hemelytra usually with a distinct clavus (fig. 159), clavus always 
ends behind the apex of the scutellum, forming the commissure. 
(Species having the wings much reduced or wanting should be 
sought for in both sections.) 
f. Antenna; very short; meso- and metasternum composite; eyes 
always present. 
