404 Transactions. 
is usually 03mm. (Fig. 1.) 
With regard to the eggs first deposited on the 11th March: By 10 p.m. 
on the 18th none had incubated ; but at 10 a.m. on the 19th a single larva 
was found in the phial. This I killed and mounted. These eggs, and 
those left on the oyster-shell, were kept under observation until the end 
of the month; but no further incubation took place. The eggs were then 
thrown away. 1 
The eggs on the sandstone block were observed constantly until 
10.30 p.m. on the 24th. On the 25th no observation was made. At 
10 a.m. on the 26th two larvae were found in the dish, evidently incubated 
not more than a very few hours earlier. As none of these eggs were 
deposited before the evening of the 12th March, the incubation period 
had been about fourteen days, as against eight days in the first case. 
Between 4 and 5 o'clock on the same day two more completed incubation, 
and four more next day. The dish had been removed from under the 
eage. Up to the middle of April no further incubation took place, and 
I supposed that there would be no more. On the 15th September, how- 
ever, I found in the dish about a dozen very young larvae, and others 
appeared from time to time during the next four weeks. Probably about 
10 per cent. in all of the eggs on the sandstone block incubated. None 
have incubated since the 15th October. 
rom these observations it is evident that hibernation may take place 
either in the larval stage or in the egg. 
that had most of the body clear though the head and thorax were still 
inside the shell. The egg had in this case become detached, and the larva 
was having some difficulty in getting clear. (Fig. 3 Presumably he 
would have succeeded. if I had not killed and mounted him. 
It is not within the scope of this note to deal with the early stages of 
embryonic development; but it is of interest to note that six days after 
copula the eggs in the ovarian sacs are round, and that a thin shell, which 
is also round, is already formed. f 
In September of this year I isolated over a dozen females that had 
emerged in copula, giving them the most favourable conditions I could 
