296 
Hermaphroditism etc. in Pediculus 
SPECIMENS 34-38 are all of £ type and have $ and $ genitalia more 
or less developed, legs I and III being of $ and $ type respectively. Only 
one example, No. 34, presented an extruded vesica penis, the basal plate 
and dilator being deformed; there are two gonopods, a $ ventral plate and 
a prolapse beneath the gonopods. No. 35 showed a medio-ventral bladder¬ 
like prolapse bearing sensory hairs and rudimentary gonopods with their 
component parts widely separated; the specimen also showed two testes 
filled with spermatozoa, likewise some eggs. Nos. 36-38 had median or 
lateral invaginations of the $ genitalia, these forming irregular sacks bearing 
sensory hairs. The dorsal bands, when clearly visible through being pigmented, 
were fragmented. 
Cross V. Capitis $ x corporis . $: yielded but one generation composed 
of 75 <J<£, 26 ??, 7 hermaphrodites and one specimen with abnormal legs (see 
pp. 319, 320); the $$ predominate (69 per cent.). 
SPECIMENS 39-45. But one hermaphrodite, No. 39, is of <$ type, its 
? characters consisting in the structure of leg III, the presence of lateral 
ventral invaginations representing the rudiments of $ genitalia. Nos. 40-45 
are of £ type with gonopods and posterior abdominal lobes, their herma¬ 
phroditic characters being evident because (a) some have fragmented dorsal 
bands, ( b) leg-pair I in almost all is of $ type, (c) in two the posterior abdominal 
lobes are asymmetrical and bifurcated, (d) the rudiments of $ genitalia are 
represented by more or less regular chitinous invaginations some of which 
are situate in the posterior lobes, others being in the penultimate abdominal 
segment; in one case the vesica penis is more developed and protruded. 
Internal organs: eggs are present in nearly all the hermaphrodites, one 
containing about 10 well developed operculated eggs besides a left testis 
with spermatozoa. 
Cross VI. Capitis $ x corporis $: yielded three generations composed 
of 693 dc?, 167 $$, and 110 hermaphrodites, their proportions being respectively 
71, 17 and 12 per cent. The first generation of this cross (Ff), contains 
128 <J<£, 16 $$, all normal. Four pairs (<£?) of the F 1 generation produced 
4 families (F 2 generation), denoted by the letters K, L, M, N, which we 
shall consider separately as follows: 
Family K (F 2 generation). 
This family consists of 104 2 $$ and 20 hermaphrodites. 
SPECIMENS 46-47, that is 2 examples, are of } type with <£ characters 
limited to fragmented dorsal bands and the structure of leg I. No. 46 is 
devoid of interest, but not so No. 47 (Text-fig. 13), with dorsal bands 
apparently slightly fragmented (obscured because gorged with blood). Legs: 
pair I as in <£, pair III as in The peculiarity of this example consists in 
