TUKNIP SAWFLY. 
81 
protruded from tlie snow. I concluded that the weevils had hyber- 
nated in the hollow stubble, and that the snow had warmed them 
sufficiently to make them crawl out. Whether they got back again, 
or whether they were all blown off the frozen surface of the snow or 
not, I cannot say, but on the 7th there were none to be seen. This 
seems to show that they do hybernate in the imago state as well as 
the larva, and in large numbers, too, as I counted forty-one lying just 
in front of me whilst walking a hundred yards across this field.” 
TURNIP. 
Turnip Sawfly. Athalia spinaruni, Fabricius. 
Athalia spinarum. 
Caterpillars, pupa, and pupa-case. Sawfly, magnified, with lines 
showing nat. size. 
In the course of enquiries regarding the Mustard Beetle and its 
caterpillar, sometimes known as “ Black Jack,” I received the following 
note from Col. Bussell, of Stubbers, near Eomford, regarding the 
caterpillar of the Turnip Sawfly, which goes popularly by the same 
name (that is, “Black Jack”); and as this insect, when it does 
appear, is rapidly destructive to Turnip-plant, I have (as suggested to 
me) added a few notes on the subject. Col. Bussell observes:— 
“ The ‘ Black Jack ’ of your Beport is not the caterpillar which I 
have known under that name. Some years ago these were very 
numerous and mischievous,—black caterpillars, something like an 
inch long, which eat oft' whole acres—sometimes whole fields—of 
White Turnip-leaves in autumn, leaving only the stalks and large ribs 
of the leaves. I have heard of flocks of tame ducks being turned 
into the fields to eat these caterpillars. Lapwings also are said to eat 
them. I do not remember seeing any of these for some years past. 
G 
