THE CHICKEN MITE* 7 
Seventh engorgement and deposition: 
During the night of September 17 12 females were placed with a host and 10 
recovered. Seven of these deposited, one of the other three died, and one died 
soon after deposition. 
Eighth engorgement and deposition: 
The eighth engorgement was made during the night of September 22. All 
of the eight females applied to the host were engorged. Six of these deposited, 
beginning September 23 and finishing September 26. One female died without 
depositing and one failed to deposit. 
On September 28, 100 per cent of the eggs deposited following the eighth 
engorgement had reached the nymphal stage, thus showing that fertility per- 
sisted though males were not with them since prior to the first feeding. 
Ninth engorgement: 
On September 28 the seven remaining females were put on a host for the 
ninth engorgement, but as only one was recovered the following morning the 
experiment was discontinued. 
A summary of the depositions, with the number of eggs deposited 
by each female, is given in Table I. 
Table I. — Summary of oviposition records of Dermanyssus gallinae, Dallas, Tex., 
1916. 
Depositions. 
Number of females depositing to 8 
eggs each. 
Total 
number 
of eggs. 
Average 
per 
female. 
Number 
of females 
depos- 
iting. 
Number 
of females 

1 
2 
3 
4 
5 
6 
7 
8 
engorged. 
First 1 
Second 

1 
2 
2 
3 
3 
2 
6 
2 


1 


4 
1 
2 


4 
1 
11 
2 
3 
4 
5 
1 
1 
14 
11 
10 
5 
2 

2 
11 
14 
6 
5 
1 
1 
4 
11 
9 
5 
2 
1 

3 
7 
1 
1 

1 


2 




203 
239 
160 
94 
48 
22 
25 
3.8 
4.98 
4.84 
4.7 
4.0 
3.14 
4.16 
53 
48 
33 
20 
12 
7 
6 
53 
Third 
49 
Fourth 
35 
Fifth 
22 
Sixth 
15 
Seventh 
10 
Eighth 
8 
1 Not recorded. 
DISCUSSION OF RESULTS OF LIFE-CYCLE EXPERIMENTS. 
No attempt was made in the experiment to see how quickly the 
life cycle could be accomplished. In the foregoing experiment the 
actual time taken for the mite to pass through its life stages was 
10 days. Under natural conditions in August without doubt this 
time would be reduced to at least 8J days. Tables II and III show 
in brief the actual time taken in the experiment and the probable 
time in nature. 
