August, 1880.] 
49 
SOME FACTS IN THE LIFE-HISTORY OF GASTROPHYSA RAPJIANT. 
BY J. A. OSBORNE, M.D. 
Having hibernated in the perfect state, underground, as I believe, 
the beetles of Gastropliysa raphani reappear in spring with the first 
warm weather at the end of March or beginning of April. At their 
earliest resurrection, still sexually immature, male and female are un- 
distinguishable, except as larger size and earlier appearance afford a 
presumption in favour of the latter sex. Very soon, however, begins 
that enlargement of the abdomen in the 5 , due to the development 
of the ovaries, and the formation of eggs in them, from w r hich the 
genus takes its name, and which, to save circumlocution in speaking 
of it again, may be conveniently designated by the term gastrophysm. 
Until gastrophysm has been, to some extent at least, developed, I 
believe there is no fertile union of the sexes. No eggs are laid until 
it has reached its full extent, when all the abdominal spiracles (four 
on each side) are completely uncovered, the elytra are tilted upwards 
reaching only to the middle of the high convexity of the abdomen, 
and even somewTat separated at the extremities. In the recently 
excluded imago, on the other hand, the dorsal and ventral segments 
of the abdomen are connected by a broad wing-like fold of skin along 
either side, in the angle of which the spiracles are seen looking directly 
upwards. 
These insects eat, both in the larva and imago states, the various 
common species of dock and sorrel. The eggs are laid on the under- 
side of the leaf, only rarely, and, as it were, accidentally, on the 
upper. The batch consists usually of 40 — 50 eggs ; and I have counted 
as many as nineteen batches on the under-side of a single leaf, and 
seen others with, I am sure, many more. The same $ will lay again 
perhaps in less than 48 hours, and will continue laying for some weeks. 
The ovipositor is telescopic-tubular. It consists of (at least) two 
pieces. The outer tube, which is exsertcd first between the semi- 
circular valves of the pygidium, and remains exserted during oviposi- 
tion, is bilabiate, having an upper and lower emarginate lip, which 
open by lateral angles. They are strengthened, especially the upper 
lip, by lateral, crescentic, chitmous thickenings, of darker colour, whose 
sharply defined convexity is towards the extremity of the lip, shading 
off less definitely forwards into the substance of the yellowish trans- 
parent tube. The upper lip, like the upper valve of the pygidium, 
has also a whitish ciliation. Shining through this upper lip, with its 
crescentic clouds, may be seen two black incrassate-linear appendages, 
