50 THE ENTOMOLOGIST. 
The imago of Nematus abbreviatus is seldom met with. 
It may, of course, have been overlooked as belonging to the 
inconspicuous mass of sawflies with white, yellow, or reddish 
knees and anterior tibiz, found nearly everywhere; but it is 
also possible that the insect is really scarce, and I admit that 
I am the more inclined to adopt this view when I call to 
mind the difficulty I had in rearing only one larva out of thirty 
which I possessed: this difficulty must also plead my excuse 
should a remark be made on the incompleteness of this life- 
history. In the beginning of May I found every year some 
green larvae, resembling that represented on our tenth plate, 
feeding on the leaves of two pear-trees in my garden. Ata 
very early stage of their existence they are found to have 
bitten round holes out of the leaves, free both of the midrib 
and of the margin of the leaf; they also rest in a somewhat 
curved position on the edge of the hole they have eaten out, 
so that they are only to be discovered by a sharp eye. 
I have never found larve smaller than that shown at fig. 1, 
so that in this case also it appears very difficult to discover 
the first and very earliest stage of the animal’s existence. On 
the petiole, however, of the leaves on which, or rather in 
which, such young larve lived, I almost always found a scar 
(see fig. 2), which appeared to me to indicate the place in 
which the egg had been concealed from which the little larva 
had proceeded. It appears that the larva move from place 
to place,—that is to say, they do not confine themselves to 
merely enlarging the hole in the leaf they at first bit out, for 
many holes are found, of the size of a silver penny, without 
inhabitant, and also leaves having two or three holes. When 
the larva has attained the size shown at fig. 3 it feeds indif- 
ferently from the margin or other part of the leaf, and, having 
hitherto always assumed a position with the back incurved, 
it now places itself as nearly as possible in a right line, so 
that even sometimes the last two or three segments project 
without any support. Larve which I had found on the 8th 
of May, of the size represented at fig. 1, had, three weeks 
later, attained their full size, as shown at fig. 4. 
The green colour of the larva in its early stages is somewhat 
of a yellow tint, afterwards becoming a grayish green on the 
back, resembling the colour sometimes observed on willow 
leaves, the ventral surface and the legs being paler, and of a 
Se 
