DIRECT INJURIES CAUSED BY INSECTS. 105 



Our friend Captain Green, of the sixth regintient of the East India 

 Company'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-Jly. 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 pro- 

 duced by the fly in question, which, however, they admit, carries the in- 

 fection from one person to another. 



You know that the hairs taken from the pods of DoUchos pniriens and 

 urens L., commonly called Cowhage and Cow-itch^, occasion a most vio- 

 lent 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 procession moth (^Cnethocampa processioiiea) of which Reaumer has 

 given so interesting an 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 

 tumors, occasioned by short hairs, or fragments of hair, brought by the 

 wind.^ Of this nature also is the famous Pityocampa of the ancients, the 

 moth of the fir [Cnethocampa Pityocampa), the hairs of which are said 

 to occasion a very intense degree of pain, heat, fever, itching, and rest- 

 lessness. It was accounted by the Romans a very deleterious poison, as 

 is evident from the circumstance of the Cornelian law " De sicariis^^ 

 being extended to persons who administered Pityocampa.^ 



the other side of my barriers ; but though they now and then settled on the naeshes, 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 {Ent. 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 possi- 

 bility 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 iis accuracy, I have been told by a friend 

 that he was assured by a gentleman, who had traveled 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 i.n it. At Venice where no horses are kept, it is said there are no house flies, a state- 

 ment which I regret not having heard before being there, that I might have inquired as to 

 its truth. 



' 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 allu(led to, and perhaps also of the larva of Euprepia Caja (the Tiger- 

 Moth), might probably be equally eflScacious. 



* Reaum. ii. 191. 195. According to Dr. Nicholai, the processionary caterpillars also 

 secrete from the external surface of their skin a sharp juice which assumes a farinaceous 

 form, and is very injurious to those that inspire it, causing workmen, who are occupied in 

 woods where the caterpillars are numerous, to sicken very rapidly. (Burmeister, Manual 

 of Ent. 510.) 3 Mouflfet, 185. Plia. Hist. Nat. 1. xxxviii. c. 9. Amoreux, 158. 



