BULLETIN 553, U. S. DEPARTMENT OE AGRICULTURE. 
fertilization can take place soon after molting and before feeding, 
and it can take place also after feeding. Directly after molting 
the females will feed, but the males will not. No doubt each male 
is able to fertilize several females, so that immediately after molt- 
ing this is all the male 
desires. Xormally ferti- 
lization takes place off the 
host, though it is conceiv- 
able that occasionally it 
may take place on the 
host. The females begin 
depositing eggs within 
about 12 hours after feed- 
ing. They will feed and 
deposit fertile eggs re- 
peatedly with only one 
fertilization. Under ob- 
servation this was done 
eight times. No doubt 
under natural conditions 
these females would have 
been visited by males sev- 
eral times. A single feed- 
ing during warm weather 
is all that is necessary for 
each deposition. A very 
small number of mites 
failed to oviposit after having had one good feeding. An engorged 
female is shown in figure 2. 
Fig. 2. — The chicken mite : Female mite engorged 
-with blood. Greatly enlarged. (Bishopp and 
Wood.) 
LIFE-CYCLE EXPERIMENTS. 
The following outline gives an accurate record of the life cycle as 
worked out at Dallas, Tex. : 
First-stage nymph engorgement: 
August 6. 6 p. m. Several hundred first-stage nymphs put in jar with fowl. 
August 7, 9 a. m. 542 engorged first-stage nymphs recovered. 
First-stage nymph molting: 
August 8, 7.30 a. m. Many have molted to second-stage nymphs. 
Second-stage nymph engorgement: 
August 9, 5.30 p. m. All the second-stage nymphs (perhaps 50 of the 542 died) 
put in jar with chicken. The nymphs are very active. 
August 10, 9 a. m. 263 engorged nymphs recovered. 
Second-stage nymph molting and mating: 
August 11, 9 a. m. Many have molted. Several pairs found to be in position 
of copulation. 
