EXTERNAL PARASITES 223 
Fie. 54. Female fowl tick, as seen from above and beneath. Greatly enlarged. 
(Bishopp ) 
nymphs. The feeding habit of nymphs is different in that they re- 
main attached to the fowl for but a short time, at night. Nymphs 
molt two or three times, alternating with feeding periods before 
they become adults. The adult female tick is shown in Fig. 54. 
Contrary to the habits of many ticks the adult female does not 
die after depositing eggs. She may alternate feeding periods on 
the fowl with egg laying for three, four, or even seven times. 
Ticks display a remarkable ability to exist for long periods with- 
out food. Seed ticks have lived for 54% months without food, those 
in the first nymphal stage for nine months, those in the second’ 
nymphal stage for 15 months, and adults for 2% years. 
Combating ticks. The difficulties associated with eradicating 
ticks frem a hen house are so great that in case the building is of 
little value, burning the structure would save time and trouble. 
Under conditions forbidding the employment of this extreme and 
effective measure, various substances may be sprayed on the wood- 
work and in the cracks. Crude Beaumont petroleum, carbolized 
whitewash, boiling water, strong kerosene emulsion and various creo- 
sote disinfectants have been recommended. Hot tar eliminates 
cracks and imprisons ticks. Ticks are very resistant to substances. 
such as insect powder, kerosene and even fumigation with hydro- 
