SEVENTEENTH ANNUAL REPORT. 



455 



The American Dog Tick { Derma centor elecius).'^ 

 (Figures 186-214.) 



Specific diagnosis — Dermacentor: Differs from D. reticulatus in following characters: 

 Stigmal plate finely punctate. 



ifaZe.— Scutum with milky white rust, reproducing anteriorly the shield of the 

 female (pseudo-scutum); the rust forms on each side 

 a long band with sinuous borders extending from the 

 anterior point of the shield to the two extreme fes- 

 toons of the posterior border. These bands leave 

 laterally two red brown spots 

 (separated by a narrow trans- 

 verse white band) and the 

 marginal border where there 

 are two white spots opposite 

 the dark spots. Between 

 their divergent posterior ex- 

 tremities the two longitudinal 

 bands are united by two other 

 parallel longitudinal bands 

 occupying a third of the length 

 of the shield, and only the 

 borders and posterior extremi- 

 ties of which are white. All the festoons are brown except 

 occasionally the extremes of each side; punctations larger 

 and deeper. Capitulum: digit of the mandibles 130 to 140 /i 

 long, thicker, the internal apophysis almost terminal; palpi 

 shorter and more convex laterally than in the female; dorsal retrograde projection 

 of second article not very prominent. Stigmal plates comma-shaped to elongate 

 oval. Legs: coxse IV do not extend caudad of the middle of the peritreme; other- 

 wise like the male of D. reticulatus. 

 Female, straighter. Scutum 



Fig. 216.— Stigmen of 

 male Dermacentor^ ni- 

 tens, from ear of pony. 

 Porto Rico. Greatly 

 enlarged. Original. 

 B.A.I. Coll. 3102. 



Fig. 215.— Stigmen of female Der- 

 maccntornitevs, from ear of pony. 

 Porto Rico. Greatly enlarged. 

 Original. B.A.I. Coll. 3102. 



217. — Dorsal view, capitulum of male D. nitens. 

 B.A.I. Coll. 3102. 



Fig. 218. 



-Ventral view of 

 same. 



straighter, more elongate, with a scarcely distinguishable sinus on posterior third of 

 lateral border; anterior emargination limited by two acute projecting angles; cervical 

 grooves deep anteriorly, superficial in the posterior two-thirds; yellowish white rust 



^Synonymy and Bibliography. 



1844: Dermacentor electus Koch, 1844, p. 235; type locality, Pennsylvania. — Idem, 

 1847, p. 109, pi. XXII, figs. 83, 84.— Salmon & Stiles, 1901, pp. 455, 456, 



