EXCRETION. 31 
macentor nitens, Rhipicephalus sanguineus, and others, remain mated 
for nearly the entire period that the female remains attached. 
Others, including the species of Amblyomma that we have studied, 
remain in the position of copulation for comparatively short periods. 
Considerable difficulty has been experienced by the writers in 
getting the sexes of the species of Amblyomma and Dermacentor 
(except D. nitens) to copulate, and there remains much to be learned 
in relation to this habit. 
Prof. Lounsbury has made some interesting observations of the 
mating of Amblyomma hebreum, a species the habits of which are 
quite remarkable. He has found that the female goes in search of 
the male, the latter accepting the female only after having attached 
and fed for several days. 
SECRETIONS. 
Several investigators have found that ticks secrete substances 
that prevent the coagulation of blood. Thus Sabbatini (1898) 
demonstrated that the bodies of [zodes ricinus, both male and female, 
- contain an anticoagulin, and Nuttall and Strickland (1908) demon- 
strated the presence of anticoagulin in the salivary glands and intes- 
tines of Argas miniatus. Christophers (1906, pp. 10, 45) reports 
observations first made by Donovan of a secretion from the coxal 
glands of Ornithodoros savignyi when engorging. This secretion, 
which was abundant (several large clear drops forming in quick 
- succession), is alkaline to litmus and has a marked effect in prevent- 
ing the coagulation of blood. A similar secretion has been observed 
by the writers to be exuded from the coxal glands of Ornithodoros 
turicata, O. talaje, and O. megnini. Studies of the glands of ticks 
_ have recently been made by Elmassian (1910) and Kiinssberg (1911). 
EXCRETION. 
All ticks excrete more or less, particularly while attached to a host 
and engorging. During incubation and when about one-half of the 
period has passed, a white spot appears at one side of the egg. This 
spot, which is apparently an excretion of the embryo, is the first gross 
sign of the viability of the egg. After hatching this excretion still 
adheres for some time to the anus of the larva, but is finally removed. 
When seed ticks are hatched out in tubes the sides often become 
spotted with the white excretions. In the free stage after each molt 
small drops of either white or black excrement are voided, but it is 
during the engorgement of the adults that this is particularly notice- 
able. The ticks of the genus Dermacentor are the most offensive in 
this respect and none can compare with Dermacentor nitens, which, 
while engorging, constantly excretes a substance which, when dry, 
_ resembles coagulated blood. 
