Gr. H. F. Nuttall 
131 
appended protocols, is considerably greater than has previously been 
recorded, and it is to be attributed to the insects having had unlimited 
opportunities of feeding. 
The parents (1st generation) 1 of the lice experimented upon, when 
received from Mr Bacot, 2. vi. 1917, were placed in a wristlet where 
they laid eggs which yielded larvae that were raised to maturity in the 
wristlet. 
Expt. 1. 5 S3 and 7 (2nd gen.) that emerged 18. vi. 17 (Day 1 
of the protocol) were isolated in a wristlet worn by my Laboratory 
Assistant (C. H.). The insects copulated on Day 1 and began to lay 
the day following: 
Day . 1 2 3 4 5 6 7 8 9 10 11 12 13 
No. of eggs laid by 
7 ??. 0 1 42 57 53 50 55 65 58 39 42 38 13 Total 513 
On the night of the 12th day of the experiment, my Laboratory 
Assistant unfortunately slept in bedding that contained naphthalene, 
with the result that the adult lice were found dead on the morning of 
the 13th day, only 13 eggs having been laid prior to the death of the 
insects during the night. In 10 days (Days 3-12) the females laid 
499 eggs; about 71 apiece or an average per day of 7-1. The appor¬ 
tioned numbers laid per day per female during the 10 days were roundly 
6, 8, 7, 7, 8, 9, 8, 5, 6, and 5. All the eggs found on the morning of the 
13th day hatched out normally, showing that the naphthalene, whilst 
killing the parents, had no effect upon the nits. 
Expt. 2. 2 S3 and 3 ?? (2nd gen.) that emerged 23. vi. 17 (Day 1 
of the protocol) were isolated in a wristlet worn by me. The insects 
copulated on Day 1 and began to oviposit next day as follows: 
Day . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 
No. of eggs laid 0 4 13 17 16 18 20 20 23 17 20 26 17 13 11 14 
by ~~3?? 2^ 
Day . 17 18 19 20 21 22 
No. of eggs laid 5 6 5 5 4 1 Total 275 
^__ j 
by 1? 
AVhereas in the previous experiment all the adults died on the same 
day by accident, in this experiment the deaths occurred in succession, 
the two males died on the 10th and 12th, the 3 $$ on the 12th, 16th 
1 Lot 210, obtained from a girl’s head, London. 
9—2 
