392 



BUREAU OF ANIMAL INDUSTRY. 



Fig. 58.— Digit of 

 mandible of 

 same. After 

 Neumann, 1896, 

 p. 10, fig. 9. 



denticles and teeth, with points directed toward the tick's body, 

 enables the parasites to hold 

 so firmly to their victim that 

 it frequently happens that 

 the capitulum is torn from 

 the bod}^ of the tick and left 

 in the skin of the host when 

 an attempt is made to re- 

 move the parasites by force. 



(5) The polypi (figs. 52-55) 

 are inserted on the base of 

 the capitulum, in some cases 

 rather dorsally, in others rather ventrally, 

 one on each side of the haustellum. Each 

 pcdpus is composed of four articles joined 

 together in a row by articulations (fig. 59). 

 These articles are called: First ^ or hasal, 

 article (nearest the base of the capitulum); 

 second^ or antepenultimate^ article,' third^ 

 OY penultimate^ article; diW.^^ fourth^ or apical^ article. They are more 



or less excavate on their 

 median or internal side (the 

 side toward the mandibles 

 and hypostome), so that they 

 form a more or less distinct 

 sheath to these structures. 

 Their veiitral^ dorsal.^ lateral 

 (or external)^ and median 

 (inner) aspects vary in ap- 

 pearance in different ticks. 



Fig. 59. — Longitudinal section 

 through a palpus of Boophilus an- 

 nulatus. The articles are black, 

 the articulations dotted. Note the 

 pore {])) which pierces the entire 

 cuticle. Original. 



Fig. 60.— Scutum and scutellum of female Boophilus an- 

 nulatus, showing mouth parts, porose areas (p. a.), and 

 eyes (e). Greatly magnified. Original 



Fig. 61.— Dorso-submedian porose plate 

 of Dermacentor reticulatus. Greatly 

 magnified. Original. 



The palpi are provided with hairs, bristles, edges, angles, and spines, 

 which vary in different ticks. 



