1899-1900. J Dr R. Stewart MacDougall on Genus Pissodes. 341 
pines imagos which had passed the winter of 1896-97 in beds 
as full-grown larvae, perhaps some as pupae. I placed nine of 
these on a pine on 12th July, and removed them to fresh material 
on 2nd August. The proof that they had bred was afforded on 
24th December, when I dissected the plant and found larvae (I may 
add that on other material they continued to lay till September), 
a brood of new beetles issuing in July 1898. 
If we start a cycle at this stage we might get three generations 
in the two years, thus : — Eggs laid in July would give imagos in 
the following June or July, and these proceeding to reproduction, 
a new brood might issue in late autumn of the same year, which, 
overwintering as imagos, would lay their eggs in the following 
spring, from which imagos would be developed in summer. Pro- 
fessor Nlisslin (8) of Karlsruhe by dissection showed that when 
beetles issued their genifal organs were not fully developed. He 
believes that Pissodes, which appear in the spring from larvae, 
which have overwintered as such, are able sooner to proceed to 
reproduction than those Pissodes imagos which issue in summer as 
a result of eggs laid in the same year, these latter imagos appear- 
ing* with their reproductive organs in a less complete condi- 
tion, and so a longer time elapsing before they can pair efficiently. 
Professor Kusslin also showed this most interesting fact that a 
female isolated in spring after copulation was able to continue the 
laying of fertilised eggs all during the summer, and even in the 
winter still held live spermatozoa. 
Length oe Life of Imago. 
Earlier in this communication I spoke of eggs being laid from 
April till September inclusive. I wish now to emphasise the fact 
that the same individual mother beetles which start to lay in the 
spring live all the summer, and can be found in September still 
laying. The males also may live through this period, copulating 
and recopulating. Kor does death of the individual necessarily 
take place at the end of one such copulating or egg-laying season, 
but as the cold weather approaches these beetles may go into 
hibernation, and reappear in the succeeding spring to renew their 
