50 IXODOTDEA^ OR TICKS, OF THE UNITED STATES. 



posteriori}^ almost angulate ; punctures large, but not very numerous, 

 and few in middle area, usually four forming a trapezium behind the 

 middle. Legs (PI. VII, fig. 8) rather large and long, the hind pairs 

 with distinct teeth beneath; coxae armed as usual. Stigmal plate (PL 

 VII, fig. 3; PI. X, fig. 4) large and very broad, in fact as broad 

 behind as long, and covered with many minute granules. 



Length of female shield, 2 mm. 



Specimens come from many places in the eastern United States, 

 from Labrador to Florida and Texas. West of the Mississippi it 

 is not common, and perhaps only introduced with stock. 



This species, described by Say, is probably identical with the Ixodes 

 cinctus of Fabricius from North America. Koch's D. electus is the 

 same species. It was considered by Neumann at first to be the Ixodes 

 americanus of Linnaeus, but later he accepted Koch's identification of 

 /. americanus as an AmMyomma^ and used D. electus for this Derma- 

 centor. Fitch's descriptions of /. rohertsoni and /. 5-striatus offer 

 nothing contrary to this form. Although the western specimens 

 might have been another species, the specimens from Virginia must 

 have been D. variahilis. 



The pattern of the white markings is practically constant, but the 

 amount of white present is variable. The species is readily known 

 by the broad stigmal plate and the minute granulation thereon. It 

 has been taken from a great variety of animals, including man, but 

 seems to prefer dogs and cattle to smaller animals, doubtless due to 

 the fact that the freshly moulted individuals climb up several feet 

 from the ground in wait for a host. In the larva tarsus I is much 

 enlarged. 



Dermacentor nitens Neumann. 



Male. — Red-brown, without markings ; legs i-ather yellowish brown. 

 Capitulum rather narrow, hind angles acute, but scarcely prolonged ; 

 palpi very short and small, shorter than the hypostome and no longer 

 than the length of the capitulum. Dorsum one and two-thirds as 

 long as broad, broadest slightly behind the middle, shiny, with some 

 punctures in front and on the sides, and behind are seven or eight 

 impressed lines; the lateral furrows are not very distinct, usually 

 three impressed grooves or furrows on the posterior half of dorsum ; 

 some scattered hairs, mostly on the sides behind. Legs rather long, 

 fourth pair (PI. VII, fig. 7) plainly larger than others, and the 

 teeth below very evident; coxa I (PI. VII, fig. 7) with the usual two 

 teeth, neither very long; coxa II with two equal projections; coxa 

 III with two tubercles, and coxa IV, which is no broader than long, 

 with the usual tooth. Stigmal plate (PL VII, fig. 10) but little 

 longer than broad, with from four to ten large, isolated granules. 



Length of male, 2.5 to 2.7 mm. 



