Rymer Jones, on Corethra plumicornis. 
99 
site was doubtful, but supposed in some degree to resemble 
that of a cysticercus, and hence the name applied to it by 
Rathke ; but Rudolphi denies that it is a cysticercus, though 
he does not know to what genus to refer it, he adds 4 an 
Cucullanus.’ (? ) 99 
On the Structure and Metamorphosis of the Larva of 
Corethra plumtcornis. By Professor T. Rymer 
Jones, F.R.S., F.R.M.S., &c. 
(Read June 12th, 1867.) 
Having towards the close of last summer met with a 
pond in my vicinity well stocked with the larvse of the 
Corethra plumicormis, objects so tempting to the microsco- 
pist, both on account of their marvellous transparency and 
the facility with which they may be obtained for observation, 
I was induced, preparatory to a more minute investigation 
of their structure, to map out, as it were, the grosser features 
of their anatomy, and thus obtain a kind of chart, the minor 
details of which could be filled up as opportunities presented 
themselves, and for this purpose sketched under the camera 
the main outlines of their economy. As the season again 
approaches when these larvae are procurable, from the study 
of which so much information may be reasonably expected 
relative to the economy and metamorphoses of the Culicidae. 
I have thought that it might possibly facilitate the explora- 
tion of other observers in this interesting field of study were 
I to place the drawings thus made at the disposal of any 
members of the Society who may feel an interest in the 
subject. 
There are indeed many points of high physiological im- 
portance susceptible of solution, by a careful examination of 
this insect in its different stages of growth, which in other 
species would seem hopelessly beyond research, owing to 
their dark hue and the general opacity of their integuments, 
whereas the glass larva, as it is not unfrequently called, 
seems eminently constructed for the purpose of courting our 
observation, insomuch that it might almost be regarded as 
purposely intended for inspection ; one of those peep-holes 
left by Providence, through which a glimpse may be obtained 
of the elaborate machinery of creation. 
It would be a waste of time, before an audience, to every 
member of which the larva in question is no doubt a familiar 
