p. Hind part of the male abdomen with two lobes. On a few wild animals. _Caparinia_ Can. pp. Hind part of the male abdomen without lobes. Live in ears of dogs and cats. _Otodectes_ Canestr. _O. cynotis_ Hering (fig. 150 e) has been taken in the United States. ee. 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; mandibles 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. BDELLIDÆ. gg. Palpi never geniculate (fig. 158a), nor fitted for grasping prey: beak small; cephalothorax with bristles in different arrangement; last segment of leg I shorter or but little longer than the preceding joint; eyes when present near posterior border. EUPODIDÆ Moniez has described a species from Belgium (TYDEUS MOLESTUS) which attacks man. It is rose colored; eyeless; 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; coxæ contiguous. CÆCULIDÆ. 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. CHEYLETIDÆ CHEYLETUS ERUDITUS, which frequents old books, has once been found in pus discharged from the ear of man.