ARACHNIDA. 259 
by their smaller size, by the absence of a well-defined head shield, by the extension 
of the shield over the whole back, and by the two pairs of chitinous plates situated 
on the abdomen behind and on each side of the anus. 
Throughout life the male enlarges but little. He becomes a little broader, longer, 
and thicker, but not markedly so. The female, on the contrary, grows to a compar- 
atively immense size (Pl. V, figs. 4, 4a, 4b, 4c), swelling day by day, her body becom- 
ing so rotund and replete with the food drawn from her host that she can scarcely 
be recognized as of the same species as the males. While her body has inflated, how- 
ever, her head, her legs, and breathing pores have not undergone any changes. ‘These 
remain exactly of the same size as in the beginning, and, with the exception of the 
head shield, are but little different from those of the male. The disparity in size 
between the legs and the body of the fully-gorged female is so marked that the legs 
and head appear even smaller than at first. The comparatively small size of the male 
has caused it to be overlooked or, if found, caused it to be classed among the young 
of this species. 
After molting, the young female again attaches herself to her host and seems rarely 
to change her position. While she may be able to do so at first with ease, she becomes 
so heavy and logy later on that any change would cause her to fall to the ground 
should she loosen her hold with her beak. The males, however, remain small and 
light, and it is not impossible for them to change their position, and no doubt do so. 
After molting, they hunt for mates through the dense growth of cattle hairs and, 
finding them, attach to their host so that they can conveniently embrace them belly 
to belly and bring their external genitals in apposition. 
When fully gorged, when the organs of generation are fully prepared, and either 
the eggs within fertilized or a sufficient quantity of semen stored in the receptacle 
for their fertilization, the female (PI. IV, fig. 4b) loosens her hold on her host and 
falls to the ground. She must do this to lay hereggs. Crawling off to some dark 
corner, her work soon begins. Any delay seems to me to be caused by the tick not 
' being prepared to undergo the final act at the time of removal from the cow. The 
female may, if detached, lay eggs any time after it is half grown. (PI. V, fig. 4c.) 
Most ticks under my observation have waited a day or two before commencing 
ovipositing, and some e.en mere. While the tick prefers to act in quiet, she will, 
if retarded long enough, show her secret method under almost any difficulties. 
I must now draw attention to an organ which, though accessory, plays an impor- 
tant réle in ovipositing. Between the mouth ring and the head shield is a space 
which becomes very marked in the fecund tick. At this point open glands, which 
are paired, racemose, and situated just under and within the head shield. During 
the last days of the growth of the ticks these glands become distended with a viscous 
fluid substance with which the eggs are to be coated for protection. 
The first visible act in ovipositing is the withdrawal of the mouth ring and append- 
ages apparently into the body, thereby leaving a depression or pocket. At the same 
time the ovipositor protrudes toward the bulging skin at the back of the mouth 
ring until they touch. The head is nowentirely concealed. As soon as the ovipos- 
itor touches the opposing organ at the slit which appears in its middle, an egg 
passes from it and is immediately surrounded by the coating sac. This passage of 
the egg is difficult to detect, but if the passage is interfered with can be made out 
after a time. The ovipositor then withdraws, the mouth parts appear, and the egg 
is pushed from its coating sac, which recedes from around it. As the mouth parts 
are commonly known as the head, it appears as though the female passed the eggs 
over her head and laid them from her neck. A curious affair, surely. 
The object of coating the egg has been clearly demonstrated by Bertkau, who 
found that eggs laid after destroying the coating sac and preventing the eggs being 
covered dried up and would not hatch, while others newly laid by the same female 
and coated hatched in due time. Egg after egg does the little creature lay, her pile 
growing constantly larger, while her body constantly contracts, until in about a 
week little is left but a yellowish, dried-up, shriveled skin, whence all life has 
departed. 
ee 
i a 
