SEVENTEENTH ANNUAL REPORT. 



411 



is apparent that in changing from the hexapod to the octopod stage 

 0. Megnini passes a resting pupa- like stage. This is by no means 

 surprising, since the differences between the hexapod and the octopod 

 stages of the Argasidae are far greater than those 

 between the corresponding stages of the Ixodidae. 

 This is apparently the stage which Townsend (1893) 

 interpreted as an egg. 



The specimens in question were taken on post- 

 mortem examination from the ear of cattle in San 

 Dimas, Cal., by Mr. M. L. Eckels, and sent with 

 other stages of the same tick to this laboratory for 

 determination. ^ ^ ^ loo.-Ear tick after 



This tick is remarkable for the difference in shedding the nymph 

 appearance between the young spiney stage and originar''^^^ enlarged, 

 the adult form, a difference that is so great that 

 the two stages have been described as belonging to different species. 



The ear tick has been reported to this Bureau a number of times, 

 notably from Texas, New Mexico, California, Kansas, and Nebraska. 

 It was originally described from Mexico b}^ Duges, who gave the fol- 

 lowing account of it: 



Argas Megnini Alf. Dug.^ — This epizoon, very abundant in the State of Guanajuato, 

 is found on the horse, the ass, and the ox, principally in the ears, and is spread fre- 

 quently to other animals, in particular to man, for I have often removed it from the 

 ear passage of children, and even of adults. 



The body of the Garrapata, wider anteriorly than posteriorly, in the shape of a 

 guitar, is less depressed than that of the Turicata. It is covered with little horny 

 spines, the color of mahogany, surrounded by a border at the base; the general color 

 is lead color, with legs of deep yellow. The male, very small compared with the 

 female, and yellowish when it is fasting, has large legs comparatively, the largest 

 being those of the pair IV. The legs are more robust than those of the Turicata, 



^ Argas Megnini Alf. Dug. — Este epzoario, abundantfsimo en el Estado de Guana- 

 juato, se halla sobre el caballo, el asno y el buey, principalmente dentro de las ore- 

 jas, y se pega con frecuencia (\ otros animales, en particular al hombre, puee no pocas 

 veces lo he extirpado del conducto auricular de ninos y aun de adultos. 



El cuerpo de la garrapata, mds ancho hacia adelante que hjlcia atras, en forma de 

 guitarra (panduriforme), es menos deprimido que el de la Turicata; esta cubierto de 

 pequenas espinas corneas (v. fig, 1), color de coaba, circundados por un rodete en la 

 base (fig. 4); el color general es aplomado, can las patas de un aleonado bajo. El 

 macho (fig. 3), muy chico respecto a la hembra, y amarilloso cuando estd, en ayunas, 

 tiene las patas mas largas respectivamente, siendo mds grandes las del cuarto par. Las 

 patas (fig. 5) son mas robustas que de la Turicata, apartadas una de otra (fig. 2), y 

 con dificultad se distinguen las ancas; hay dos espinitas debajo del ultimo arti'culo. 

 Las piezas bucales salen de un repulgo circular; las maxilas tienen en la extremidad 

 dos laminas bidentadas (fig. 8, a) y la lengiieta (fig. 8, b) estd pro vista de dientes 

 dirigidos hdcia atrds y mds agudas en el macho que en la hembra. 



Como se ve por esta breve descripcion, puramente diferencial, no se pueden con- 

 fundir las Turicatas con las Garrapatas. Parecen estas ultimas menos nocivas; a lo 

 menos es mas facil hacerles soltar la presa, e impedir que dejen su rostro en la herida; 

 muchas veces basta el aceite para obligarlas d desprenderse. 



