170 Biology of Pediculus humanus 
No. of 
adults 
and sex Longevity 
Remarks 
Authority 
Bacot n. 
1917 
corporis 
1 cJ 32 days 
whilst it fertilized 18 9 
p. 236 
7 $ * respectively 23, 29, 30, 32, 34, 
44, 46 days (average 34 
days) 
p. 236 
corp. + cap. 
1 d 1 1 9 45 days 
female laid normally 
p. 255 
capitis 
4 d 1 respectively 7, 12, 15, 30 days 
— 
pp. 246-247 
16$ respectively 11, 14, 17, 20, 
22, 25, 26, 29, 31, 31, 34, 
34, 36, 37, 38 days (average 
27 days) 
pp. 246-247 
(d) Longevity of corporis and capitis when offered unlimited 
opportunities of feeding on'the body by the felt cell and wristlet 
methods in my experiments. Only the longest lives recorded. 
No. of 
adults Longevity Remarks Authority 
corporis 1 <5 1 9 28 days, $ 29 days ... on skin of arm ... Nuttall 
capitis 1 $ 1 9 <J 23 days, $ 22 days ... in wristlet ... ... ,, 
1 Bacot, ii. 1917, p. 234. 2 Engelhardt, 1915, p. 165. 3 Fantham, 1912, p. 513. 
4 Galli-Valerio, 1913, p. 501. 5 Galli-Valerio, 1916, p. 37. 6 Hase, 1915, p. 67, cited 
by Muller. 7 Heymann, in. 1915, p. 253. 8 Heymann, 18. viii. 1915, p. 308. 
9 Muller, 1915, p. 74. 10 Noeller, 1915, abstr. 11 Peacock, 1916, pp. 40, 50. 
12 Sikora, 1915, pp. 164, 533. 13 Warburton, 1911, jip. 23-27. 14 Wilder, 1911, 
p. 43. 15 Fiebiger, vm. 1915, p. 645. 16 Galewsky, in. 1915, p. 286. 17 Sergent 
and Foley, in. 1914, p. 471. 18 Nocht and Halberkann, 1915, p. 626. 
Summary regarding the longevity of Adult Lice when fed. 
Corporis. The foregoing records show that a female may live up 
to 30 days when kept at 28° C. and fed once daily; when fed twice 
daily and kept at 24° by day and ca. 35° by night, the male may live 
35 and the female 45 days; when afforded an opportunity of feeding 
during 6-7 hours out of the 24 on the person and carried in the pockets 
during the interim, the maximum age attained by a male was 32 days 
and by a female 46 days (Bacot’s average for 7 females = 34 days). 
When kept continuously on the body and given unlimited opportunities 
of feeding, as in nature, the longest lives observed were 28 days for a 
male and 29 days for a female. Bacot’s corporis + capitis hybrids: 
a male and female fed for 6-7 hours out of the 24, lived 45 days. 
Capitis. The longest lives recorded for a male and female fed for 6-7 
hours out of the 24 were 30 days and 38 days respectively (Bacot’s 
average for 16 females = 27 days). When kept continuously on the 
