DIRECT INJURIES CAUSED BY INSECTS. 69 
Our friend Captain Green, of the sixth regiment of the East India Com- 
any’s native troops, relates to me, that in India, when the mangoes are ripe, 
which is the hottest part of the summer, a very minute black fly makes its 
appearance, which, because it flies in swarms into the eyes, is very 
troublesome, and causes much pain, is called there the eye-fly. At this 
season the eyes are attacked by a disease, supposed to be occasioned by 
eating the mangoes, but more probably the result of the irritation produced 
by the fly in question, which, however, they admit carries the infection 
from one person to another. 
You know that the hairs taken from the pods of Dolichos pruriens and 
urens L., commonly called Cowhage and Cow-itch', occasion a most violent 
itching, but perhaps are not aware that those of the caterpillars of several 
moths will produce the same disagreeable effect. One of these is the pro- 
cession-moth (Cnethocampa processionea), of which Reaumur has given so 
interesting av account. In consequence of their short stiff hairs sticking 
in his skin, after handling them, he suffered extremely for several days ; 
and being ignorant at first of the cause of the itching, and rubbing his eyes 
with his hands, he brought on a swelling of the eyelids, so that he could 
scarcely open them. Ladies were affected even by going too near the nest 
of the animal, and found their necks full of troublesome tumours, occa- 
found that by extending over the outside of his windows nets of'a very fine pack- 
thread with meshes 14 inch to the square, so fine and comparatively invisible that 
there was no apparent diminution either of light or the distant view, he was enabled 
for the remainder of the summer and autumn to enjoy the fresh air with open win- 
dows without the annoyance he had previously experienced from the intrusion of 
flies, often so troublesome that he was obliged on the hottest days to forego the 
luxury of admitting the air by even partially raising the sashes. “But no sooner 
is observes) had I set my nets than [ was relieved from my disagreeable visitors. 
could pereeive and hear them hovering on the other side of my barriers; but 
though they now and then settled on the meshes, I do not recollect a single instance 
of one venturing to cross the boundary.” 
It is singular, too, as was first pointed out by Mr. W.B. Spence (nt. Trans. i. 
7.) that Herodotus 2200 years ago stated that the Egyptian fishermen protected 
themselves in a similar manner from the attacks of mosquitos by spreading their 
fishing-nets over their beds; a fact which has greatly puzzled all his commentators, 
who, not conceiving the possibility of mosquitos being kept off by fishing-nets, which 
must necessarily have wide meshes. have supposed the father of history to have 
alluded to some protection of fine linen similar to the gauze nets now used against 
these insects. But in this, as in so many other instances, the supposed error is not 
that of Herodotus, but of his commentators, who, ignorant of the fact above related 
as to flies being excluded by wide-meshed nets, could not conceive of it in the case 
of mosquitos; yet, in confirmation of its accuracy, I have been told by a friend that 
he was assured by a gentleman, who had travelled in America, that he had often 
had mosquito nets with meshes an inch square put over his bed, and had found them 
a perfect security from their bites, though, as is well known, they will creep through 
any small hole in an ordinary gauze net. 
In concluding this long note it may be observed that the number of house flies 
might be greatly lessened in large towns, if the stable dung, in which their larvae are 
chiefly supposed to feed, were kept in pits closed by trap doors, so that the females 
could not deposit their eggs init, At Venice, where no horses are kept, it is said 
there are no house flies; a statement which I regret not having heard before being 
there, that I might have inquired as to its truth, 
1 Cowhage has been administered with success as an anthelmintic, as has likewise 
spun glass pounded; the spicula of these substances destroying the worms. The 
hair of the caterpillars here alluded to, and perhaps also of the larva of uprepia 
Caja (the Tiger-Moth), might probably be equally efficacious. 
P38 
