Digestion is extremely slow and fowl blood may be identified 

 by the precipitin test for at least 23 months after ingestion 

 (Gozony, Hindle, etnd Ross 1914). 



The following notes are chiefly from Hooker, Bishipp, and 

 Wood (1912). Many more details may be found in their report. 



Usually females oviposit after each meal, which may number 

 up to six or seven in a lifetime. Under exceptional conditions, 

 a female may require two blood meals before laying eggs. The 

 greatest number of eggs deposited after the first few blood meals 

 increases progressively from 195 to 646, but decreases after sub- 

 sequent feedings to as few as 47 eggs following the seventh or 

 last feeding. The average nvimber of eggs laid after each engorge- 

 ment was: first, 131; second, 159; third, 133; fourth, 110; fifth, 

 97; sixth, 95; seventh, 47. Eggs are laid in the adult tick's 

 retreat, 



Ovi position generally commences four to ten days after feeding, 

 in stimmer sometimes as early as the third day. In winter or in the 

 absence of males, egg laying may be delayed for weeks or months, 

 Oviposition of moderately large batches continues over a six to ten 

 day period but only three days are required for depositing a small 

 niimber of eggs. In nature it appears that the fowl argas seldom 

 engorges and oviposits more than five times, unless females com- 

 mence feeding early in the spring. 



Incubation of eggs extends over an eight to eleven day period 

 in warm summer weather, but in cooler climates or seasons this pe- 

 riod is extended to three weeks or even longer. 



As stated above, larvae generally feed for from five to ten 

 days, but they may complete engorgement in three or four days, and 

 Rohr (1909) recorded two days. There is some indication that qviiet, 

 setting hens allow the greatest number of lai;^ae to thrive, and 

 that different breeds of hosts exert no influence on larval deveL- 

 opment. In NA1'EU_3 laboratories, Dr, Herbert S. Hurlbut (unpub- 

 lished J is finding that only a moderate number of larvae kills 

 chickens used in his experiments, apparently not doing so by trana- 

 mission of pathogenic orgamsms or by exsanguination. Nymphs and 

 adults resvilting from these larvae have no observable deleterious 

 effect on their hosts. Reasons for this exceptional larval toxic- 

 ity have not yet been ascertained, 



- 68- 



