308 ORDER II. HEMIPTERA. 



of fruits and flowers. In this whole order, perhaps not a 

 single species is of any known utility in medicine or the 

 arts, (though numbers are extremely beautiful and curious,) 

 excepting the flies called cantharides; on the contrary, 

 many of them are injurious to vegetation, or consume the 

 fruits of human industry. . 



The cantharides, so valuable in medicine, from forming 

 the principal ingredient of the common blistering plaster, 

 differ considerably from each other in size ; the largest are 

 about an inch long, and as much in circumference. Some 

 are of a pure azure colour, others of a pure gold, and some 

 a mixture of both ; however, they are all very brilliant, 

 and extremely beautiful. They are chiefly natives of 

 Spain, Italy, and Portugal ; but in the summer are to be 

 found near Paris, on the leaves of the ash, the poplar, 

 and the rose ; as well as among wheat, and in meadows. 

 The country people, it is said, expect them every seven 

 years ; when they appear in such swarms in the air, that 

 the atmosphere to some distance is impregnated with their 

 offensive smell, which is a guide to those whose business 

 it is to catch them. When dried, fifty of them will scarcely 

 weigh a single dram. 



ORDER II HEMIPTERA. 



THIS order is much smaller than the preceding : its dis- 

 tinguishing character is, that the insects which compose it 

 have four wings, the two superior of which are semi-crus- 

 taceous and incumbent, that is, the interior edges lie one 

 above the other. 



Some of these insects, as the cock-roach, are found 

 about bakehouses ; others, as the camel-cricket and the 

 locust, feed on grass, and every species of vegetable; while 

 the boat-fly, the water-scorpion, and many others, frequent 

 lakes, rivers, and standing pools. 



