258 INSECTS AFFECTING DOMESTIC ANIMALS. 
0.50 by 0.30 of an inch. When gorged with blood they are nearly as 
thick through as they are broad. In the freshly hatched hexapodous 
young, and the young in the next stage of growth, the thoracic shield 
is one-third the size of the whole body, which is pale yellowish, with 
very distinct crenulations on the hinder edge. The fourth pair of legs 
are added apparently at the first molt. It is called ‘gar apata’ by the 
inhabitants of Nicaragua.” 
Curtice gives the life history in considerable detail, and the follow- 
ing extracts will-show the essential points: | 
On October 10 I placed some of these eggs (PI. V, fig. 5) in a small, glass-covered 
dish filled with damp mold and set it aside in the incubating room of the laboratory. 
On November 4 the young ticks (PI, V, fig. 6) had begun to emerge, and by November 
15 the hatching was completed, each egg having produced a young tick. 
At this time the ticks were taken to the bureau experimental farm and put on a 
calf which was confined in a stable, whose temperature was maintained at summer 
heat throughout the experiment. A calf with a white abdomen was selected, thrown 
on its back, sprinkled with ticks directly on its fine, silky hairs, and time allowed for 
them to crawl into the skin. In this proceeding the certainty of the young ticks 
arriving at the most suitable surroundings was assured. * 
It is well to state here that the parents of these young ticks were the last seen at 
the station on any of the cattle, and that the room of experiment and the calf were 
quite free from ticks before the experiment began. The following table will serve 
to illustrate the sequence of events in the experiment and present it in rough but 
compact form: 
Date. Stage of experiment. Time consumed in various stages. 
Oct. 3 | Egg laying begun. 2 secs acne ca casdmen AALIOTGOnOBOCEOMOE 
Oct ed00) ioe layne tnt hed- seece ee eca ee ease sae one setae oe Ovipositing 1 week. 
Nove. 4) |) Dekssappeareds 25-25. 3 - <aeetrccemesie Meiers cower Hatching 3 and 4 weeks. 
Wows WG | Vcore hayes ley qitiice coseo SaccocossbosoodspopEcEcon Ss pquedae” Unnecessary interval of 1 week. 
Nove 22!) Birst molt, larva, toomympheses sas. 2. se oeseseeei oer Larval stage lasted 1 week. 
Nov: 29) | (Second molt, nymph to adult =< 2222-22 e ee aie ..-..| Lasted 1 week. 
Dec 11) |-Kemalerhalfiorown with male eaccsit = oeee seiseee ee ee About 2 weeks later. 
(Deca 16) | Ex perinient Closed. nsercsaee tosses ee clei eee ee About 1 week. 
Experiment ENn@uUred scat omie asics ac eerie ener About 24 months. 
The eggs were laid in a little mass, were subovoid, dark brown and opaque, and 
coated with some protective substance. In alcohol they show a thin, shell-like cov- 
ering, with a dark, opaque mass within. In the latter stages of incubation the form 
of the young ticks became more and more apparent until they emerged. The exit 
from the shell seemed to be by the shell rupturing and the imprisoned occupant 
thrusting it off with its feet. The torn edges afterwards rolled inward and produced 
the appearance of clam shells, so frequently mentioned in writings on this subject. 
The larva is six-footed, possesses no sexual organs, and wants the large, single 
stigmata found in later stages. 
The next or nymphal stage, as seen through the skin of the larva, bas added a pair 
of limbs behind the others and a pair of large stigmata behindthem. The additional 
legs lie along the sides in a loop with its convexity directed caudally. The contents 
of the three front pairs of legs have withdrawn until only their white tips remain 
in the testa about to be molted. 
The difference between the ticks destined to become either male or female during 
their final molt is not marked. The average of the males is smaller, but a small 
female may not be any larger than an ordinary male. In each the mouth ring and 
mouth parts, the shield-like headpiece, the breathing pores, the limbs, and the body 
are alike. 
After they emerge, however, the males (PI. IV, figs. 1 to 3) can be quickly chosen 
see ee 
