ON PARTHENOGENESIS—ANTL-SERA. 265 
a 
No weakening of the strains is perceptible. The former has never yet yielded a male 
among some 1200 specimens reared. 
Sexuality of Pristiphora pallipes, Lep.—tIn all, about 900 specimens have been bred, 
all females except eight males and two sexual abnormalities. All the males, except 
one, and one abnormality, were produced under circumstances which make it 
impossible to state decisively whether they were experimental products or not. 
Studies in the sexuality of these rare males continue, and the evidence is strongly in 
favour of the view that the species has developed parthenogenesis to such a degree 
that the males have become superfluous and dispensable, despite the fact that micro- 
scopic investigation shows that the insects produce spermatozoa. A paper is in 
preparation. 
Morphological work on the genitalia of both sexes and of the second abnormality— 
a gynandromorph with external genitalia pertaining to both sexes—is well forward 
for publication. 
Numerous sex-change experiments by the following method have given negative 
results this season. The eggs laid and reared in an incubator at a temperature of 
30° C. have consistently yielded females up to now. (Cf. results cited in previous 
Report for year 1924 at Toronto.) 
Pteronidea (Nematus) ribesii, Scop—A detailed study of a gynandromorph 
obtained in breeding experiments has been written up for publication in the July 
number of the British Journal of Experimental Biology. This specimen, externally, 
was predominantly female whilst, internally, it was genetically male. It produced 
spermatozoa, attempted to pair as a male, and was itself inseminated by a male. 
The paper also devotes special attention to sexuality in the saw-flies. 
The germ cells of the gynandromorph also afford material for cytological study, 
and this is being pursued pari passu with investigations into the cytological conditions 
of normal specimens from the late Professor L. Doncaster’s and the Secretary’s own 
material. 
Parthenogenesis in Lepidoptera.—The following papers have been completed : 
1, Animal Parthenogenesis in relation to Chromosomes and Species. American 
Naturalist, Vol. LIX., No. 662, May-June, 1925. This paper arose out of the Secretary’s 
contribution to a symposium between Sections D and K at the Toronto meeting of 
the Association. 
2. In collaboration with Dr. J.W.H. Harrison. On Parthenogenesis originating 
in Lepidopterous Crosses. T'ransactions of the Natural History Society of Northumber- 
land, Durham, and Newcasile-wpon-Tyne (in the press). 
In both these papers the results attending certain hybridisation experiments, by 
Dr.J.W.H. Harrison, with the two moths, Tephrosia bistortata, Goeze, and 7’. crepus- 
cularia, Bkh., are recounted and discussed from various aspects. The crossings have 
resulted in an Fl hybrid which, by parthenogenesis, yields F2 offspring which 
demonstrate segregation in wing colour and pattern and in sex. The first paper 
suggests how such parthenogenesis and segregation could give rise to new forms, and 
the second claims to present the first definite proofs of how hybridisation may originate 
parthenogenesis. Further work is in progress. 
Pre-natal Influence of Anti-sera on the Eye-lens of Rabbits. 
—Preliminary Report of Committee (Prof. W. J. Daxtn, Chairman ; 
Mr. J. T. Cunnineuam, Secretary; Prof. D. M.S. Watson). Drawn 
up by the Secretary. 
Ty September 1924 I had obtained four young albino rabbits—two males and two 
females—and also one doe which was white but not a perfect albino, having some sooty 
colour on the snout and ears. Although several trials were made, no copulation occurred 
between these rabbits until February 4, 1925, when one of the does, Albino No. 1, was 
found to be in heat and was successfully mated. This doe was not injected or made the 
subject of any experiment, but simply allowed to produce young as a control, to see 
if the young were normal with regard to the eyes and in other respects. It is usually 
stated in the practical breeders’ books that the period of gestation in domesticated 
rabbits is thirty days, and it is stated by biologists that ovulation and fertilisation take 
place immediately after coition. This doe, however, had no young on the morning of 
March 6 when the period of thirty days from mating was completed. She had a nest 
