302 
Hermaphroditism etc. in Pediculus 
No. 96 differs from the foregoing in having complete dorsal bands and 
two gonopods, the ? ventral plate not being annular. 
Family M (F 2 generation). 
This family consists of 19 S3, 28 and 10 hermaphrodites. 
SPECIMENS 97-98, 2 examples, are of £ type with gonopods and 
posterior abdominal lobes well developed; the 3 characters being reduced to 
fragmented dorsal bands, the structure of leg I, and, in one specimen, the 
bipartite 3 ventral plate. 
SPECIMENS 99-106, 8 examples, are of § type, with 3 genitalia slightly 
or. much deformed. The 3 ventral plate varies in shape, but in most cases 
is bipartite. The $ characters of these specimens are: the $ structure of leg III; 
the $ genitalia, only well developed in one case, are reduced in the others 
to a simple or multiple invagination of very irregular shape and bearing 
sensory hairs; in a few cases there is also a slight devagination which represents 
the prolapsed vagina. One specimen shows protruded 3 genitalia of irregular 
form. 
Family N (F 2 generation). 
This family consists of 92 33, 7 $$ and 10 hermaphrodites. 
SPECIMENS 107-114, 8 examples, are of § type with posterior abdominal 
lobes and gonopods well developed; the 3 characters are: dorsal bands 
complete, fragmented, or reduced to a few chitinized spots, the 3 structure 
of leg I, and the lateral extensions to the $ ventral plate. One of these 
specimens is of special interest: 
No. 114 (Text-fig. 18): with the general appearance of a The sole 
3 character, visible externally, consists in the much fragmented and reduced 
dorsal bands. The abdomen contains many eggs of which one shows a com¬ 
pletely formed embryo. As the specimen was dried and shrivelled, and had 
to be treated with caustic potash prior to examination, the only parts of 
the embryo which are visible by transparency are the claws of its three pair 
of legs. 
The embryo had therefore undergone complete development within the 
female’s body. There is no reason to suppose that the embryo was produced 
parthenogenetically, because the female appears to be normal and emanates 
from a lot comprising males. Moreover, large numbers of virgin females 
raised in our laboratory, whilst ovipositing normally, never produced partheno- 
genetic offspring (see Nuttall, Parasitology , x. p. 141). The only plausible 
explanation of the phenomenon is that the internal genitalia of this female 
were sufficiently normal for copulation to take place, but that they presented 
some malformation which impeded oviposition. The egg, having been 
fertilized, remained imprisoned in the female and the embryo underwent 
complete development in situ. There is nothing surprising in this occurrence, 
