142 DR. J. B. HICKS, FURTHER REMARKS ON 
mixed in a small bottle, with the addition of a little water when the effervescence is brisk, | 
will in a short time remove sufficiently the colour of most insects. Some parts which are - ' 
quite black, ås the elytra of beetles, wings of bees, &c., require a day or two, and some 
even a week. The hydrochloric acid has also a valuable property in rendering the nerve- _ 
tubes more perceptible. This plan of bleaching will be found invaluable in examining 
the structure of antennæ, which are often quite black, as I shall hereafter show. 4 
I have also shown the distribution of the nerve in the wing of Tenthredo viridis: the — 
bundle of nerves going to the vesicles was well marked in the specimen from which the 
drawing was taken. i "o 
These examples will, I think, serve to point out the intimate connexion between the 
— vesicles and the nerves. Whether the whole nerve be distributed, in all instances, to these 
organs, I am inclined to doubt, since a small branch seems to pass beyond the point | 
where they cease. j i 
I shall now endeavour to trace these organs through the different tribes, so far as I have 
been able. i 
In the Hymenoptera I find that they exist far more extensively than I supposed when 
my former paper was read ; their detection has been mainly owing to the use of chlorine, 
‘so few of this Order having light-coloured nervures in the wings. The figures here given - 
represent these organs in Ophion lmteus (Tab. XXVIII. fig. 2) and Tenthredo viridis 
(Tab. XX VIII. fig. 3), two species which are good examples of the tribe, and in which the 
nervures are the most transparent. These organs in the Wasp (Vespa vulgaris), Honey- ' 
bee (Apis mellifica), Andrena fulvicans, and Tenthredo lucorum, having a great resem- - 
blance to the above, I have not thought it worth while to figure them. 
They consist of two groups on the upper, and one scattered group on the under side of _ 
the subcostal nervure, amounting in Ophion to 200-300 above, and perhaps 100 beneath, 
with a smaller group at the end of the nervure. 
With regard to the Diptera I have nothing to add to my former remarks, excepting | 
that I have found the vesicles in Hippobosca equina distinctly marked both in the — 
halteres and wings. . The diameter of each vesicle is 3300 inch. 
In Tipula oleracea they are also well shown on the wings. 
In the Hemiptera they are very scanty; I have observed and drawn those on the — 
second wing of the Tree Bug, a species of Pentatoma. HM 
In Notonecta glauca, or the Water-boatman, they are even more simple. `° 
In Corysus I have been unable to find them. I have carefully examined the elytra of © 
the common Bed-Bug (Cimex lectularius), but cannot find anything definite; some papilla - 
occur on them, but they do not seem to be arranged in any distinctive manner. i 
In the Coleopterous group we find them highly developed, as may be observed in the — 
- drawing of these organs in Strangalia elongata in Plate XXVII. fig. 1. 
They occur in numerous groups on the subcostal nervure, mostly at the widest part, 
but are also scattered along it to the joint of the wing, where we find about ten or twelve — 
large vesicles in a group, after which they cease. | 
a the Carrion Beetles (Necrophorus) they are very well developed, as also in Silpha, 
where they are rerharkably large, considering the size of the insect. 
