ENTOMOLOGY

THE BIOLOGIES AND HABITS OF TICKS 431from the host the greater part of the time, imbibing blood rapidly whenfavorable opportunity offers, such as when the hosts are at rest at night.The first or seed tick stage of this group of ticks, huwever, usually remainson the host for several days. The adults of this family partake of bloodmeals several times and the females deposit a number of batches of eggs.The total number of eggs deposited is usually much smaller than in thecase of the ticks in the other family.Among the Ixodid ticks we find but one species which has the habitof feeding rapidly, as in the Argasidae. In the other species each stageremains on the host for at least several days. Even in the same genus,however, we find widely different habits as regards feeding. There aresome forms in which the larvae and nymphs leave the host for molting.In several species molting takes place on the host and the tick does notdrop off until it has become replete as an adult, while in still otherinstances, the first molt takes place on the host and the second on theground. In all cases in this family the engorged females deposit a largenumber of eggs and die soon after. In most species copulation takes placeon the host. The males may remain some time after the females havedropped. In certain species of the genus Ixodes, however, it appears thatthe males never attach to the host, but remain in the places frequentedby the host and when the females drop off they are fertilized by them.A few species have been found. to deposit fertile eggs without the interventionof the male. The eggs of practically all Ixodids are deposited ina single mass in some protected place. They hatch almost simultaneouslyin a few weeks' time and the larvae or seed ticks usually crawl upon vegetationand there await the passing of a suitable host. In the case of thosespecies which drop from the host for each molt, sometimes spoken of asthree-host species, it is necessary for the ticks to secure a host on threedifferent occasions, hence undoubtedly increasing the mortality beforematurity is reached.Many species show a predilection for attachment to certain regionsof the host. Structure or habits are sometimes modified to fit the conditionsunder which the ticks live on the host. There is a tendency with allticks to choose the more tender portions of the skin upon which to attach.Hence' with many of our common forms we find groups of ticks betweenthe forelegs, on the brisket or the inguinal region. The habit of attachingin the ears has already been mentioned in connection with Ornithodorosmegnini (Duges) Neumann. The tropical hor§c tick, IDermacentor nitensNeumann, also has this habit well developed. The Gulf Coast tick, Amblyommamaculatwm Koch, is usually found in the ear but never in thedeeper portions of that organ. On small animals there is also frequentlyexhibited a tendency of the ticks to attach in the region where they areleast in danger of being destroyed by scratching or biting.