ee dB. 
THE COCOONS OF 
BY GEORGI 
The cocoons of Cionus scrophulariae 
furnish an illustration of striking simi- 
larity of form of insect structures. to 
parts of a plant. Geoffroy!, in 1762, 
without, of course, perceiving any cause 
for this similarity, writes of this species : 
‘“‘When their larvae, after having de- 
voured the leaves of the Scrophularia, 
have arrived at their full size and are 
ready to transform, they make at the 
tip of the stems a sort of slightly trans- 
parent bladder in which they enclose 
themselves and undergo their metamor- 
puosis. This and quite 
bladder appears to be produced by a 
viscid moisture with which the larva 
is covered. How can the insect form 
this round vesicle with this sort of 
glue? This [ have been unable to per- 
ceive. I have only found the larvae 
just enclosed in this vesicle; I have 
seen them there the form of 
pupae, and finally the perfect insect has 
come out of them before my _ eyes. 
These vesicles are of the size of the 
shells which contain the seeds of the 
Serophularia and are often mingled with 
them; but they are easily distinguished 
round firm 
under 
1 Geoffroy, E. L. 
se trouvent aux environs de Paris... 
297. 
Histoire abrégée des insectes qui 
1762, V. 1, Pp. 277; 
DIMMOCK, 
CIONUS SCROPHULARIAE. 
CAMBRIDGE, MASS. 
by their transparency and by their round 
form that differs from the fruit of the 
Scrophularia, 
point.” 
which terminates in a 
Again the same author writes, 
“This larva forms at the extremity of 
the branches, near the flower-buds a 
round shell resembling a bladder, where 
it undergoes metamorphosis and from 
which, at the end of several days, I have 
seen the perfect insect emerge.” The 
preceding is the earliest mention I have 
found of the cocoons of Cionus. About 
a dozen writers have since written notes 
upon and descriptions of the cocoons 
of the genus. 
Hermann Miiller?, in 1879, figures 
cocoons of C. scrophulariae on a sprig 
of Scrophularia writes of 
them, ‘‘We find a_ still more delusive 
similarity of cocoons to other objects, 
and indeed in this case to objects imme- 
diately around them, that is to the 
ovaries of the plant on which they are 
found, in a common little curculionid, 
Cionus scrophulariae, which feeds in 
the state upon the leaves of 
Scrophularia nodosa and spins itself for 
pupation into brown oval cocoons on 
the blossom and fruit stems of the 
nodosa and 
larval 
2 Miiller, H. Schiitzende aehnlichkeit einheimischer 
insekten. (Kosmos, bd. 6, p. 119.) 
