408 



BUREAU OF ANIMAL INDUSTRY. 



The Spinose Ear Tick (Ornithodoros Megnini)? 



(Figures 65-67, 82-108.) 



Specific diagnosis. — Ornithodoros: Adult. — Body phial-shaped; sHghtly attenu- 

 ated anteriorly, broadest at legs II, slightly constricted near legs IV, broadly 

 rounded posteriorly; color brown to violet or black. On the surface, symmetrical 

 depressions, one arciform, longitudinal, from each side of the projection corre- 

 sponding to the capitulum; lateral and slightly 

 anterior of this, an infundibuliform depression; 

 in back, along the lateral border, a longitudinal 

 groove of variable length, sometimes interrupted; 

 a median groove occupying the greater length of 

 the posterior half. Ventral surface: Preanal 

 groove absent, replaced by a first postanal groove 

 at a tangent to the anal slit, straight and joining 

 the coxal groove; the true postanal groove near 

 posterior border; a broad anal groove terminating 

 at this postanal groove. Subcoxal and coxal folds 

 broad, well marked, the latter not passing coxae 

 II, and the coxal groove passing between coxae I 

 and II, extending backward to the second post- 

 anal groove and disappearing on the sides near the 

 posterior angle of the body. Stigmata circular, 

 250 jii in diameter, stigmal pore semilunar. Anal 

 valve broader than long (150 to 200 ju by 200 to 

 250 ju), each lip provided with short hairs. Eyes 

 absent. Tegument slightly rough (shagreened), forming an irregular mosaic, strewn 

 with numerous fine, short hairs. Reticulate fossettes occupy the ventral and dorsal 

 depressions; others scattered here and there. 



On the ventral surface between the two postanal grooves, extremely small and 

 hard spines. Capitulum very small and short; 150 ju from base of palpi to extremity 

 of hypostome. Maxillae slender, 490 m long, digit 75 m, stalk slightly and insensibly 

 swollen proximally. Internal apophysis of digit thick, provided with four teeth, 

 two terminal nearly perpendicular to each other, and two intermediate, smaller; 

 external apophysis with superior tooth slightly salient, inferior tooth large, bent 

 backward; median tooth well developed. Hypostome blade-shaped, broad at the 

 base, rounded at the extremity, unarmed.^ Palpi thick, 300 ju long (90 ju, 85 //, 65 ju, 

 60 JU, from first to fourth article) , with articles relatively broad and short, the second 



Fig. 81.— Two sense organs on tarsus I 

 of embryo of Argas miniatus. Greatly 

 enlarged. Original. 



^Synonymy and Bibliography. 



1883: Argas Megnini Duges, 1883, pp. 196, 197.— Megnin, 1885, pp. 466, 472-475, pi. 



XXI, figs. 1-8.— Neumann, 1888, p. 96.— Idem, 1892a, p. 101.— Idem, 1892b, 



p. 105.— Railliet, 1893, p. 718.— Dolly, 1894, p. 980. [See also Neumann, 



1896, p. 42, as syn. of Ornithodoros Megnini.'] 

 1893: Argas americana Packard" of Townsend, 1893, pp. 50-52. 

 1895: Rhynchoprium spinosum Marx, 1895, p. 199, pi. ii, figs. 1-li. — Osborn, 1896, 



pp. 255, 256, pi. Ill, figs. 1-li. [See also Neumann, 1896, p. 42, and Stiles & 



Hassall, 1891, p. 1, as syn. of Ornithodoros Megnini.'] 

 1896: Ornithodoros Megnini (Duges) Neumann, 1896, pp. 42-44, figs. 36 a-b.— Ward, 



1900a, p. 199, fig. 3.— Stiles & Hassall, 1901, pp. 1, 2.— Salmon & Stiles, 



1901, pp. 408-414, figs. 65-67, 82-108. 

 ^ Megnin describes and figures teeth in five transverse rows, of which the first on 

 each half comprises only one tooth, and the last four; none of Neumann's or our 

 preparations corresponded to this description. 



