D. Keilin and G. H. F. Nuttall 
303 
for several cases are known of accidental viviparity in oviparous insects. 
As instances we may cite the observations of Lowne (1895) on Callij)hora , 
Roubaud (1909) on Pycnosoma , Guyenot (1913) on Drosophila, Keilin (1916) 
on Aphiochaeta, Phora, Calliphora and Mucsa 1 . 
SPECIMENS 115-116, 2 examples, are of $ type , and sexually non¬ 
functional. 
No. 115 is fairly dark, with dorsal bands complete, leg 1 as in J, leg III 
as in $. A genitalia reduced, deformed, completely imprisoned in the body. 
A ventral plate bipartite. $ genitalia invaginated and strongly chitinized. 
Posterior end of body irregularly truncate. 
Text-fig. 18. Pediculus humanus, cross between capitis and corporis. Specimen 114, Abdomen, 
with outline of eggs, viewed by transparency, one egg containing a fully developed larva 
as seen by the claws (cl.). (N. del.) 
No. 116 with dorsal bands slightly fragmented, legs as in No. 115. 
genitalia completely imprisoned, reduced, deformed. $ genitalia invaginated, 
consisting of irregular, strongly chitinized structures. Posterior end of 
abdomen rounded as in 
1 Consult Keilin, D. (1916). “Sur la viviparite chez les diptcrcs et sur les larves de diptcres 
vivipares.” Arch. zool. cxpcr. et rjdn. lv. 393-415 (contains bibliography). 
Parasitology xi 
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