DISEASES OF INSECTS. 211 



a more intense degree of plethora. When I examined 

 this appearance the fly had fallen off, and I could not 

 find it. 



Mr. Sheppard once brought me a panicle of grass, the 

 glumes of which were rough with hairs, or small bristles, 

 to which several specimens of a fly related to Xylota 

 pipiens adhered by their proboscis. At first I thought 

 that having been entrapped by the bristles, and unable 

 to extricate themselves, they had perished from want of 

 food; but since when touched they readily dropped from 

 the glumes, some other cause, perhaps disease, probably 

 occasioned this singular suspension of themselves. 



The maladies to which bees and silkworms are subject 

 are more interesting to us than those of flies, on account 

 of their utility as cultivated insects. One of the worst 

 distempers which attacks the first of these animals is a 

 kind of looseness or dysentery : this happens early in the 

 year, when they are fed with too much honey without 

 any portion of bee-bread % and sometimes destroys whole 

 hives. Their excrements, instead of a yellowish red, 

 then become black, and the odour they emit is insupport- 

 able ; the bees no longer observe their usual neatness, 

 inducing them to leave the hive when they void their ex- 

 crements, but they defile it, their cells, and each other. 

 Several remedies have been prescribed for this disease. 

 To prevent it, a syrup made by an equal mixture of 



8 Dr. Bevan asserts (The Honey-bee, 197) " that we have no evi- 

 dence that pollen constitutes any part of the food of adult bees." Had 

 he consulted Reaumur (v. 418) he would have found that this great 

 man examined the proceedings of a bee with a magnifying glass, 

 and distinctly saw her devour very deliberately the masses of pollen 

 on her hind legs. He says also (Ibid. 419.) that if the stomach and in- 

 testines are opened, they will be found filled with that substance. 



P 2 



