174 
Biology of Dermacentor 
another male attempts to displace the male in this position, whereupon 
he sets up a vigorous seesawing with his hind legs across the abdomen 
of the female which prevents displacement by the attacking male. The 
mouth-parts of the male are inserted into the genital orifice of the 
female and when they are withdrawn the male deposits a sperma- 
tophore, the neck of which is inserted into the female orifice 1 . It 
appears that the spermatic fluid is then pressed out by the male. 
After the act the male usually attaches itself to the host beneath the 
female. The entire act consumes less than 50 minutes though the 
exact time has not been determined. A female has been observed to 
copulate at least three times, and males may copulate two or more 
times. 
The spermatophores (PI. X, fig. 7) obtained have been partially or 
wholly collapsed, hence their original shape could not be definitely 
made out. They appear to be almost globular with a neck which is 
broadest at its base. When collapsed they are deeply concave on the 
side next to the female and the neck appears to be grooved along one 
side. The tip of the neck is curved toward, and inserted into, the 
vulva. The size of the three collapsed spermatophores measured was 
889 microns, 918 microns, and 932 microns in length (including neck), 
and 531 microns, 646 microns, and 617 microns in width, respectively; 
the neck measured about 287 microns in length. The spermatophore 
becomes cemented to the body of the tick by a substance exuded by 
the male, which hardens when dry. After copulation the body of the 
spermatophore lies just posterior of the genital opening with the neck 
extending anteriorly to the opening into which the tip is inserted. 
The males move about considerably, especially after most of the 
engorged females have dropped off. Sometimes several males are found 
attached close to a single female at the same time. The females 
copulate at any stages of their engorgement on and after the fourth 
day following moulting. 
Summary of the non-parasitic period. As previously stated, the 
preoviposition period ranges from 7 to 134 days, the incubation period 
from 33 to 71 days, and the larval longevity from 50 to at least 346 
days. The combined periods from the dropping off of the engorged females 
to the death of the last larva, or the non-parasitic period, range nor¬ 
mally from 159 to at least 479 days. Table III gives a summary of 
this data. 
1 Compare with the observations of Nuttall and Merriman (in. 1911) Parasitology, 
iv. 39-44, Fig. 1. 
