288 
Account of a curious Insect. 
[Sept. 
In order to use this table, there is required only the whole amount of the varia- 
tion, and the time from the nearest barostice , if I may be allowed to coin a word, 
expressive of the stationary state of the barometer. 
Enter the Table with the time from the nearest maximum or minimum, (barostice) 
at top, and opposite the oscillation at the side, is the correction to be applied to the 
observed altitude of the Barometer. 
Example. 
In May, 1830. Maximum, 29,678 at 9 *40 
Minimum, ,560 at 4 ’00 
Oscillation, ,118 
Required the height at noon, 12 — 9 *40 = 2*20 time from maximum. 
Height at maximum, = ,678 
Under, 2 *20 and opposite. ,118 is ,034 
Height by Table, ,644 by observation 647. 
VII. — Account of a curious Insect. 
To the Editor of Gleanings in Science. 
Sir, 
In a recent number of the Lancet, giving an account of a lecture, by Mr. 
Lawrence, on poisoned wounds, the following observations occur ; — “ in the stings 
of insects there is a small wound inflicted, and there is an acrid matter introduc- 
ed into the wound. I speak of the stings of the bee, the wasp, the hornet, and 
the tarantula spicier.” In another part of the lecture, we have this remark,— 
“ there are certain insects which bite, and which do not sting; that is, they 
make a small wound, but no venomous or acrid matter is introduced into the 
wound. This is the case with the flea, bug, gnat, scorpion, &c. the bites of these 
insects produce slight inflammation.” Now with reference to the first quotation, 
I have my doubts about any of the Aranea having a sting, and the prejudice of 
the tarantula being so armed, is, I imagine, founded in vulgar error, just as it was 
common to say, that a snake stings. The fact is, I believe, that spiders inject 
poison into a wound made with fangs — that is to say, from hollow, arched, pointed, 
and moveable books attached to each jaw (a. fig. 3.J ; if I am right then, the taran- 
tula has no sting. 
With reference to Mr. Lawrence’s other remarks, I am rather surprised that he 
should fall into the mistake, of classing the sting of the scorpion among the bites of 
fleas, hugs, and gnats. I need scarcely dwell on a circumstance so familiar to 
all of us here, as that the scorpion has a sting, by means of which he inoculates a 
venom when irritated. Neither am I convinced that Mr. Lawrence is quite 
correct, when he says, that certain insects, as the gnat and bug, bite, making a 
small wound, but into which no venomous matter is introduced. I am rather in- 
clined, on the contrary, to conclude that a venomous or acrid matter is always 
introduced — for mosquito bites, for instance, swell, at times, very much, and even 
ulcerate. This, I believe, is more especially the case with their bites at the period 
of copulation. 
It remains for me next to advert to a circumstance which may be well known 
to some philosophical observers,- but which to ine is new. In the month of 
August, I saw upon the fringe of a punka, that had just been attached to the frame, 
after returning from the washing, a number of minute insects, weaving delicate 
gossamer threads. I at first thought they must be minute spiders, — although 
their working socially together soon made me reflect, that this could not be the 
case. They looked more like very small, light colored, black headed ants, than 
any thing else, and several of them were busily and actively engaged on the cloth 
of the punka fringe— and on the thread they were weaving down from it ; and 
clinging to which they were visible, like sailors in the riggingof a ship, rapidly going 
up and down, or slanting out a new thread, in the direction of those already spun. 
I lie scattered threads they had thrown down, waved with the slightest breath of 
«ui ; and the rapidity with which they worked was surprising ; for all at once new 
ireads' shone forth, where none were visible before, ' The following rude sketch 
' k r * •) may give you an idea of them as they first appeared. 
. tj 6 , Q k a * 6 The cloth Fringe, c The Insects on the cloth, cl The Gossa- 
mer threads, and the Insects busy upon them. 
