THE BEETLE. 389 



summer time, upon the leaves of the ash, the poplar, and the 

 rose-trees, and also among wheat, and in meadows. It is very 

 certain, that these insects are fond of ash-leaves, insomuch that 

 they will sometimes strip one of these trees quite bare. Some 

 affirm that these flies delight in sweet-smelling herbs ; and it is 

 very certain, that they are fond of honey- suckles, lilac, and wild- 

 rherry shrubs ; but some that have sought after them declare 

 they never could find them on elder-trees, nut trees, and among 

 wheat. We are told that the country people expect the return 

 of these insects every seven years. It is very certain, that such 

 a number of these insects have been seen together in the air, 

 that they appeared like swarms of bees ; and that they have so 

 disagreeable a smell, that it may be perceived a great way off, 

 especially about sun-set, though they are not seen at that time. 

 This bad smell is a guide for those who make it their business 

 to catch them. When they are caught they dry them, after 

 which they are so light, that fifty will hardly weigh a drachm. 

 Those that gather them tie them in a bag, or a piece of linen 

 cloth, that has been well worn, and then they kill them with the 

 vapours of hot vinegar, after which they dry them in the sun, 

 and keep them in boxes. These flies, thus dried, being chymi- 

 cally analysed, yield a great deal of volatile caustic salt, mixed 

 with a little oil, phlegm, and earth, Cantharides are penetrat- 

 ing, corrosive, and, applied to the skin, raise blisters, from 

 whence proceeds a great deal of serosity. They are made use 

 of both inwardly and outwardly. However, it is somewhat 

 strange that the effects of these flies should fall principally upon 

 the urinary passages ; for though some authors have endeavoured 

 to account for this, we are still in the dark, for all they have 

 said amounts to no more than that they affect these parts in a 

 manner which may be very learnedly described, but very ob- 

 scurely comprehended. 



An insect of great, though perhaps not equal use in medicine, 

 is that which is known by the name of the Kermes ; it is pro- 

 duced in the excrescence of an oak, called the berry-bearing 

 ilex, and appears at first wrapt up in a membranaceous bladder, 

 of the size of a pea, smooth and shining, of a brownish-red co- 

 lour, and covered with a very fine ash-coloured powder. This 

 bag teems with a number of reddish eggs or insects, which be- 

 ing rubbed with the fingers pour out a crimson liquor. It is 



