34 American Midland Naturalist Monograph No. 1 



NYMPH 



Shape and size about as in the adult. 



The integumental markings of the nymph very different from those of the 

 adult. Entire surface, dorsal and ventral, smooth and shining, with fine reticu- 

 lations and transverse striae, similar to the body wall of larval Argasidae. 



Spines. — Spines or hairs are present over the entire surface of the body 

 except in the area immediately surrounding the mouth parts; more abundant 

 and longer at the anterior end; progressively smaller toward the posterior end; 

 less numerous on the ventral surface. 



Discs. — Definite discs are absent but corresponding depressions are some- 

 times evident. These depressions are free of spines and in some a few fine 

 punctations are visible. 



Legs. — Short and moderately heavy. Subapical protuberances absent or 

 small on tarsi I, II, and III, but distinct on IV. Length of tarsus I, 0.36; 

 metatarsus, 0.30. Length of tarsus IV, 0.45; metatarsus, 0.45. 



Coxae. — Present as inconspicuous sclerites. 



Hood and Camerostome. — Absent. 



Capitulum. — In ventral view the capitulum is in a depression formed by a 

 circular tumescence which makes it difficult to get a true impression of the 

 shape of the basis capituli unless it is dissected out. Broader than long. Palpi 

 moderately heavy (more slender than in megnini), and with article 1 lacking 

 the distinct ventral swelling found in the adult. Hairs small and few in 

 number. 



Hypostome. — Large, with sides nearly parallel, denticles long and sharp, 

 in a s l$ arrangement with the denticles about equally long in the basal and 

 apical regions; denticles in the corona absent or few in number. Marginal den- 

 ticles absent in the subapical region. Length, 0.30. 



Folds. — Coxal and supracoxal folds are faint or absent. 



Grooves. — True grooves are absent but the preanal and median postanal 

 grooves are indicated by shallow, elongated depressions. 



Spiracle. — Circular, mildly convex. 



This species resembles the well-known spinose ear tick, O. megnini, but is 

 readily separated by the following characters: its smaller size; the heavy V- 

 shaped spines found on the anterior surfaces in megnini are replaced in 

 lagophilus by slender spines which are the same as those on the posterior parts; 

 denticles on the hypostome in a 3 / 3 pattern instead of 4, 4 ; legs more slender; 

 spiracles of the nymph mildly convex instead of conically protuberant. 



In common with megnini, the adults of lagophilus are not parasitic. In our 

 experience the nymphs are attached in the fur on the face of the rabbit near 

 the vibrissae. One living adult (17850) was found at the entrance of a rodent 

 burrow; another (19270) was found well down in a burrow. 



