FRANCIS WILLUGIIBY. 
89 
that covers the cells before the change ? For here 
the old bee, when she hath provision enough, 
with an egg closes up the cartrage, and hath no 
more to do; the maggot, a great while after, making 
the theca, which is analogous to the cover of the 
cells.” 
There is another letter, relating to the subject 
of Mr Willughby’s, dated July 10, 167 1 - 
Among many other of his communications to 
the Philosophical Transactions concerning insects, 
there is one dated August 24, 1671, which 
deserves insertion. 
The title of it is, “ Concerning the Ichneumon 
Wasps, and their several changes, ways of breed- 
ing, especially that of laying their eggs in the 
body of caterpillars.” The inquiries which it 
describes were suggested by the opinion of Mr 
Lister, that the ichneumon wasps so deposited 
their eggs. 
“ These insects have four wings, antennse like 
bees, their body hanging to their breast by a very 
slender ligament, as in wasps ; most, if not all, 
have stings, and come from a maggot which spins 
herself a theca before she turns into a nympha. 
There is a great variety of them. Some breed 
as bees do, laying an egg which produceth a 
maggot, which they feed till it comes to full 
growth ; and others, as we guess, thrust in their 
eggs into plants, the bodies of living caterpillars, 
maggots, &c. 
“ For it is very surprising to observe, that a 
great caterpillar, instead of being changed into a 
