Acarina 
271 
pp. Hind part of the male abdomen without 
lobes. Live in ears of dogs and cats 
.. . Otodectes Canestr. 
0 . cynotis Hering (fig. 150 e) has been 
taken in the United States. 
:. Palpi usually of four or five segments, free; rarely with ventral 
suckers near genital or anal openings; eyes often present; tarsi 
never end in suckers; body usually divided into cephalothorax 
and abdomen; rod-like epimera rarely visible; adults rarely 
parasitic. 
f. Last segment of the palpi never forms a thumb to the preceding 
segment; palpi simple, or rarely formed to hold prey; body 
with but few hairs.EUPODOIDEA. 
g. Palpi often geniculate, or else fitted for grasping prey; mandi¬ 
bles large and snout like; cephalothorax with four long 
bristles above, two in front, two behind; last segment of leg I 
longer than the preceding segment, often twice as long. 
. BdELLID/E. 
gg. Palpi never geniculate (fig. 158a), nor fitted for grasping prey: 
beak small; cephalothorax with bristles in different arrange¬ 
ment; last segment of leg I shorter or but little longer than 
the preceding joint; eyes when present near posterior 
border . Eupodid^e 
Moniez has described a species from Belgium (Tydeus 
molestus) which attacks man. It is rose colored; eye¬ 
less; its legs are scarcely as long as its body, the hind 
femur is not thickened; the mandibles are small and the 
anal opening is on the venter. The female attains a 
length of about 0.3 mm. 
ff. Last segment of the palpus forms a thumb to the preceding, which 
ends in a claw (with few exceptions); body often with many 
hairs (fig. 158 k).TROMBIDOIDEA. 
g. Legs I and II with processes bearing spines; skin with several 
shields; coxae contiguous.C/ECULID.E. 
gg. Legs I and II without such processes; few if any shields, 
h. Palpi much thickened on the base, moving laterally, last 
joint often with two pectinate bristles; no eyes; legs I 
ending in several long hairs; adult sometimes parasitic 
.CHEYLETIDiE 
Cheyletus eruditus, which frequents old books, has once 
been found in pus discharged from the ear of man. 
hh. Palpi less thickened, moving vertically; eyes usually present; 
leg I not ending in long hairs. 
i. Coxae contiguous, radiate; legs slender, bristly; body with 
few hairs; no dorsal groove; tarsi not swollen . 
. Erythr.eid.e. 
ii. Coxae more or less in two groups; legs less bristly. 
