Mar. 24, 1923 
Biological Notes on the Hen Flea 
1009 
copula when observed and remained so for 35 minutes, until they were 
slightly disturbed and the act ended. 
The adults are killed by freezing temperature and die within a few 
hours when exposed in tubes in an incubator at a temperature of ioo° F. 
TOTAL PERIOD OF DEVELOPMENT, LONGEVITY OF ADULT FLEAS, 
AND CONDITIONS AFFECTING ABUNDANCE 
The minimum period from oviposition to the emergence of the adult 
was 30 days and the maximum period 65 days. 
Eggs, larvae, and pupae were kept in a jar with the original breeding 
media from December 8 until April 18, when some adults were still alive 
after a period of 132 days. The adults can live for a considerable time 
without food under some conditions, and an infestation will persist for at 
least two months in the adult stage if the weather is dry and cool. Adults 
die very quickly without food if the weather is hot. 
Breeding occurred during the winter of 1921-22, at Uvalde, Tex., in 
unprotected places where a large number of chickens were kept—that is, 
in open yards and under trees in which the fowls roosted. These infesta¬ 
tions increased during the winter and early spring until they were very 
heavy in the latter part of March. The fleas practically disappeared 
immediately after the heavy rains of March 29 and April 3 and 4. Two 
weeks after the rains it was unusual to find a flea on the fowls in such 
places if the latter were not permitted to go under buildings. It has been 
observed that the fleas become abundant during the fall or spring of the 
year when the weather is cloudy and dry, a condition that occurs fre¬ 
quently in southwestern Texas. Infestations are likely to occur at any 
time in cool, dry places, as under buildings and in closely constructed 
henhouses.» 
27976—23-7 
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