14 LIFE HISTORY OF NORTH AMERICAN TICKS. 
tories of some of these species is rather complete, but it seems desir- 
able to withhold from publication the results of investigations of 
these species until further data are accumulated. 
This tick investigation has been conducted, throughout, under 
the general direction of Mr. W. D. Hunter, from whom the writers 
have received many helpful suggestions. Mr. W. A. Hooker had 
direct charge of the investigation from its inception until September 
15, 1908, when Mr. F. C. Bishopp took direct charge of the investiga- 
tion and has carried it forward. Mr. H. P. Wood’s connection with 
the work has been continuous since November, 1907. Mr. J. D. ° 
Mitchell and Mr. F. C. Pratt (now deceased) contributed valuable 
assistance by collecting material and making notes on host relations 
and economic status. Mr. W. V. King, acting under the direct super- 
vision of Prof. R. A. Cooley, of the Montana Agricultural Experiment 
Station, has, by the collection of several hundred lots of ticks in the 
Northwestern States, supplied a large amount of information on the 
hosts of Dermacentor venustus and other species and some information 
upon the geographical distribution of these species. Prof. Cooley 
has also aided materially in several ways, including the sending of a 
number of specimens of Ixodes kingi, which were used in the studies of 
that species published herein. Several correspondents, particularly 
in the Western States, have furnished a large number of lots of ticks 
which have been of much value in the work. Mr. C. E. Hood, Mr. 
G. N. Wolcott, and Mr. G. W. Hood are responsible for a few of the 
counts of eggs, and these gentlemen, as well as Mr. E. A. McGregor 
and Mr. J. Jacobs, have assisted in the summarization and tabulation 
of records.’ 
CONCERNING TICKS IN GENERAL. 
SYSTEMATIC POSITION AND CLASSIFICATION. 
The ticks form a superfamily of the order Acarina, and are closely 
related to the mites which produce scab, mange, and itch. The 
superfamily Ixodoidea, to which all the ticks belong, is composed of 
two families, namely, the Argaside, represented in this country by 2 
1 Credit for taking the photographs used in making the plates in this bulletin should be given as follows: 
H. P. Wood: Plate I, fig. 1. 
F.C. Bishopp: Plate I, fig. 6; Plate III, fig. 2; Plate XIV, fig. 5. 
W. EE. Hinds: Plate II, fig. 1; Plate VI, fig. 10; Plate VII, figs. 1, 5, 6; Plate VIII, fig. 5; Plate XI, fig. 
3; Plate XIII, fig. 14. 
W. A. Hooker: Plate I, figs. 4, 5; Plate III, figs. 1, 3, 4; Plate V, figs. 1, 4; Plate VI, figs. 11, 12, 15; 
Plate VII, figs. 2, 4; Plate VIII, figs. 1,2; Plate IX, figs. 1-8; Plate X, figs.1-10; Plate XI, figs. 1, 4, 5, 7, 8, 9; 
Plate XII, figs. 1, 4,7; Plate XIII, figs. 1-13; Plate XIV, fig. 2; Plate XV, figs. 1-4, 10, 11. 
G. N. Wolcott: Plate I, figs. 2, 3; Plate II, fig. 2; Plate III, figs. 5-8; Plate IV, figs. 1,9; Plate V, figs. 
2, 3, 5-8; Plate VI, figs. 1-9, 13, 14, 16,17; Plate VII, figs. 3, 7-10; Plate VIII, figs. 3, 4, 7-11; Plate XI, 
figs. 6, 10; Plate XII, figs. 2, 3, 5, 6, 8-12; Plate XIV, figs. 1, 3, 4, 6-9; Plate XV, figs. 5-9. 
