74 PARASITOLOGY. 
rior extremity of the body, forming a mass number- 
ing, usually, 4,000 to 5,000. These eggs hatch in 
about three weeks, if the temperature is favorable. 
The larvae are small, six-legged asexual parasites. 
In this stage they have lived in a bottle for six 
months without food. They crawl over the ground 
or upon the blades of grass or weeds, and thus are 
brushed off by animals passing along. Once on the 
animal they attach themselves usually in the region 
of the thigh, between the hind legs. After one week 
they moult (passing through a change in the ana- 
tomical structure, during which time they shed the 
skin.) They are now provided with four pair of legs 
and at the end of another week they moult again, 
and become sexually mature. The males seek the 
females and place themselves in apposition, in which 
position the male can be found still alive after the 
female is fully engorged. But its life is short after 
being removed from the host; it dies within a few 
hours. The female draws blood slowly for the first 
two weeks, then rapidly for the third week, becom- 
ing fully engorged in three weeks, drops off, and is 
ready to begin ovulation; gradually shrinks during 
ovulation until she is only about one third of her 
original size, then dies. 
Condition Produced.—The tick carries the proto- 
zoa (Piroplasma Bigeminum) causing Texas or 
Splenic Fever. The larva, as soon as it gets onto 
the host, attaches itself to the skin and begins to 
draw blood. At this time it inoculates the host with 
the protozoa. The single celled parasites enter the 
red blood cells, break them up and liberate the hem- 
oglobin; the protozoa have multiplied in sufficient 
