LIFE HISTORY . 355 



The life histories of all ticks are more or less similar. After 

 several days of mating the female ticks engorge and soon after 

 drop to the ground and begin to lay their eggs (Fig. 153). These 

 are deposited on or just under the surface of the ground. Some 

 of the family Argasidse engorge several times, laying a batch of 

 from 20 to 50 eggs after each gluttonous repast. All of the 

 Ixodidse, on the other hand, lay their eggs after a single engorge- 

 ment. The eggs number from a few hundred in some species 

 to upwards of 10,000 in others and are laid 

 in rather elongate masses in front of the 

 'female. Each egg as it is passed out by the 

 ovipositor is coated with a viscid substance 

 by glands between the head and dorsal shield 

 of the tick and is then added to the mass in 

 front. The process of egg-laying occupies 

 several days, as not more than several hun- 

 dred eggs can be passed out and treated 

 with the viscid coating in the course of a 

 day. 



The eggs develop after an incubation period 

 which varies with the temperature from two pia. 153. Texas 

 or three weeks to several months. Eggs de- fever tick, Margaropus 

 posited in the fall do not hatch until the fol- "After" Grkybiiu ^^^^ 

 lowing spring. 



The larval ticks which hatch from the eggs are much smaller 

 than the adult ticks and have only six legs (Fig. 157B). They are 

 popularly known as " seed ticks." The seed ticks soon after 

 hatching climb up on a blade of grass or bit of herbage and assume 

 a policy of watchful waiting until some suitable host passes with- 

 in reach. Seed ticks must be imbued with almost unlimited 

 patience, since in many if not in the majority of cases long delays 

 must fall to their lot before a suitable host comes their way like 

 a rescue ship to a stranded mariner. The jarring of a footstep 

 or rustle of bushes causes the ticks instantly to stretch out to 

 full length, feeling with their clawed front legs, eager with the 

 excitement of a life or death chance to be saved from starvation. 

 If success rewards their patience, even though it may be after 

 many days or weeks, they feed for only a few days, becoming 

 distended with blood, and then drop to the ground again. Re- 

 tiring to a concealed place they rest for a week or more while 



