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 a , 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 
a Dr. Bevan asserts (The Honey-bee, 197) "that we have no evi. 
dence that pollen constitutes an)' part of the food of adult bees." Had 
he consulted Reaumur (v. 4 IS) he would have found that this great 
man examined the proceedings cf 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. 410.) that if the stomach and in- 
testines are opened, they will be found filled with that substance. 
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