1899-1900.] Dr R. Stewart MacDougall on Genus Pissodes. 355 
was not till the first week of September 1899 that the earliest 
beetles of the new brood issued, the escape continuing until 
26th September. 
In all the three experiments the generation is seen to he an 
annual one. 
Length of life in imago stage . — In the case of P.pini , also, a long 
life has to be chronicled. The imagos which issued (after the 
pupal stage) in March and April of 1898 lived and bred during 
this year. In November they proceeded to hibernation, reappear- 
ing above ground again on 11th March 1899. The five men- 
tioned in Experiment 3 continued to live and lay eggs during 
1899, hibernation following in November. On 9th March 1900 I 
undid the muslin sack that surrounded the pine in connection with 
which the five pini were hibernating, but could find no beetles. 
The pot had split in two, and I was afraid of losing the beetles if 
they should reappear. I therefore decided to look for them in 
their winter retreat, and on removing the surface soil carefully I 
came on a male pini which, on being taken up into the warm hand, 
soon started to move actively about. This beetle was now two 
years old, and had hibernated twice. 
As to when the imago may he got, there was no month in the 
whole year save January and December when I did not find 
feeding imagos on my plants. It was very interesting to me to 
find P. pini feeding in one case even in the month of Eebruary. 
This was on a pine where I had ten hibernating pini of a brood of 
1899. During some mild weather at the end of February 1900, 
I had the curiosity to open the sack and examine this pine, when 
I found that the beetles, tempted by the comparatively high tem- 
perature, had left their winter quarters and were feeding on the 
plant. 
General Conclusions. 
1. The Pissodes have a remarkably long life in the imago stage. 
This long life is characteristic of both sexes. 
2. Copulation and egg-laying are not single acts, which, once 
accomplished, terminate the life of the individual, but both may he 
often repeated. The same individuals which have paired and bred 
