C. Hay Murray 
315 
According to Southall, about fifty eggs are laid in each batch, and this 
would seem to be about correct, as the ovaries, which are seven egg 
tubes on each side, contain, at the most, three large ova in each of the 
fourteen. These do not show (as in the queen bee) all the stages from 
undifferentiated cells down to mature eggs, but all the ova are seen to 
be at the same stage of development. It may be inferred from this 
that the bug lays all her eggs at about the same time. According to 
Girault, a female bed bug, kept in captivity, will lay over 100 eggs in 
a period of approximately three months. This suggests that there are 
at least two laying periods per year, depending possibly on the presence 
of food and warmth, but as the writer has carried out no breeding 
experiments, he cannot vouch for Girault’s remark. 
Laying so few eggs at a time, the rapid multiplication of bed bugs 
is probably due to the fact that the eggs are laid, at each recurring 
period, in inaccessible places, and being thus undisturbed a large 
proportion come safely to the hatching. From the ovaries spring the 
oviducts. These are short tubes uniting ovary and vagina. At their 
bases on either side is a spermatheca for the storing of the sperms 
received from the male. At the level of the junction of the oviducts 
and spermathecae is the vagina, which is a narrow groove open for the 
major part of its length. It lies in the middle line between the two 
central plates, at whose lateral edges are to be found the ventral portions 
of segment seven. The bristles which arise from its edges are similar 
to the long thin one found at the base of the thick stumpy spine on the 
first tarsus of each foot. This groove receives the penis when the act 
of copulation takes place (Fig. 35). 
Appendix. 
The latest work on the bed bug appears in A Textbook of Medical 
Entomology, by Messrs Patton and Gragg, both of the King Institute 
of Preventive Medicine, Guindy, Madras, treating of various insects 
which are pests to man. One section deals with the bed bug, and the 
authors would seem to have laid undue weight on the authority of 
Landois, many of whose mistakes or defects of observation are repeated 
by them. The book was published in Madras in December, 1913, and 
in this country was not available until the end of February, after 
the foregoing paper was completed, and as it was thus too late for 
criticism in the paper itself, the writer would merely point out, in an 
appendix, what he considers to be some of the more outstanding in¬ 
accuracies. 
21—2 
