524 
HYMEXOPTERA. 
in number, and in the year 1832 they bad become so 
numerous and destructive that many vines were entirely 
stripped of their leaves by them. IVhether the remedies 
then proposed by me, or any other means, have tended to 
diminish their numbers, or to keep them in check, I have 
not been able to ascertain, and have had no further oppor¬ 
tunity for making observations on the insects themselves. 
At that time, air-slacked lime, which was found to be fatal 
to these false caterpillars of the vine, was advised to be 
dusted upon them, and strewed also upon the gi’ound un¬ 
der the vines, to insure the destruction of such of the in¬ 
sects as might fall. A solution of one pound of common 
hard soap in five or six gallons of soft water is used by 
English gardeners to destroy the young of the gooseberry 
saw-fly; and the same was recommended to be tried upon 
the insects under consideration. 
All the young of the saw-flies do not so closely resemble 
catei’pillars as the preceding; some of them, as has already 
been stated, have the form of sluo;s or naked snails. Of 
this description is the kind called the slug-worm in this 
country, and the slimy grub of the pear-tree in Europe. 
So different are these from the other false caterpillars, that 
they would not be suspected to belong to the same family. 
Their relationship becomes evident, however, when they 
have finished their transfonnations; and accordino-ly we 
find that the saw-flies of om' slucr-^vorms and those of the 
vine are so much alike in form and stmcture, that they 
are both included in the same genus. Moreover, there are 
certain false caterpillars intermediate in their forms and 
appearance between the slimy and slug-like kinds and those 
that more nearly resemble the true catei’pillars; thus admi¬ 
rably illustrating the truth of the remark, that nature pro¬ 
ceeds not with abrupt or unequal steps; * or, in other words, 
that, amidst the immense varietv of livino- forms wherewith 
this earth has been peopled, there is a regular gradation 
* “ Natura saltus non facit.” — Linnaeus, Syst. Xat. I. 11. 
