CLASSIFICATION AND HABITS OF TICKS. 45 
vials are still alive, March 1, 1907, although a number have succumbed. 
Not less surprising than the longevity of the adult is its resistance to 
insecticides. Lounsbury has kept adults confined for three months 
in a box nearly filled with flowers of sulphur with no apparent effect 
on them. He has also exposed them for two hours to hydrocyanic- 
acid gas at the strength of 1 ounce of potassium cyanid to 150 cubic 
feet of space and found that this scarcely served to decrease their 
activity. Further, many individuals survived for some days after 
treatment with paraffin and various oils. 
Genus ORNITHODOROS. 
Ornithodoros, the second genus belonging to the Argaside, is 
represented in the United States by two species, O. megnini Dug., 
and QO. turicata Dug., both known to attack man. 
A species widely distributed through Central and South Africa, 
O. moubata, was reported by Dr. Cuthbert Christy (1903), of the 
Liverpool School of Tropical Medicine, as the probable transmitter 
of tick-feverin man. In 1905 Dutton and Todd,* not knowing of the 
work of the other investigators, demonstrated that ‘‘tick-fever’’ in the 
oriental province of Kongo Free State is a relapsing fever produced 
by a spirillum, probably Spirillum (Spirachexte) obermeveri, and that 
this organism can be transmitted by the bite of the tick. 
The life cycle of members of this genus has yet to be followed. 
Lounsbury states that O. savignyi begins to engorge at once when 
applied to a host, and that generally it is off again inan hour. After 
an engorgement, he states, it rests for many weeks or months and, gen- 
erally, at least, sloughs its skin if immature or lays eggs if a mature 
female before again seeking an animal. 
It is suspected by Mr. Nathan Banks that a species of the genus 
transmits a disease of cattle in California. 
SPINOSE EAR TICK. 
(Ornithodoros megnini Dugées. ) 
This tick was first described in 1883 by Dugés, from Guanajuato, 
Mexico, as a species of Argas. It has been reported in the United 
States from New Mexico, California, Kansas, and Nebraska, and is an 
important tick in Texas. The writers are informed by a rancher in 
the western part of the State that considerable injury is due to the 
irritation produced by it in the ears of cattle and that its presence can 
often be told by the rough appearance of the hair. A prominent 
stockman in Dewitt County states that, in his opinion, it is second to 
the fever tick in importance. In addition to cattle it is found upon 
horses, asses, dogs, and sheep, and has been reported several times 
fromman. Mr. J. D. Mitchell, of the Bureau of Entomology, reports 
two cases at Victoria, Tex., in which specimens were taken from 
human ears by a physician, following prolonged severe pain. Mr. 
4Memoir XVII of the Liverpool School of Tropical Medicine. 
