318 INSECTS. HBMIPTKRA. 



visit a desert. For leagues where this innumerable host has visited, not a leaf nor 

 a blade of grass is seen ; even the bushes and trees break under their weight ; and 

 when they suddenly perish in great numbers, disease is added to famine, from the 

 pestilential air from their decaying bodies. The island of Formosa often experiences 

 such calamities; and Charles XTI. when in Bessarabia supposed he was threatened 

 with a dreadful storm of hail, when, like a cloud, these animals came to the ground, 

 and covering men and horses thickly, stopped the army on its march. In the 

 year 1749 Germany was visited by an overwhelming host of locusts, which desolated 

 that country, and extended their ravages beyond the Baltic Sea to Sweden. Their 

 descent at this time was compared to a heavy fall of snow, to a whirlwind, or to a 

 cloud of smoke extending itself with uncontrollable rapidity. Since that period no 

 very alarming visitations of this kind have occurred in Northern Europe. Super- 

 stition formerly added not a little to the horrors of an inundation of locusts. 

 From the many black spots upon the elytra, the vulgar believed that there was to be 

 read in these markings denunciations traced by the Deity, announcing vengeance for 

 their sins ; and thus all interest was taken away, in the minds of men conceived 

 themselves doomed to punishment, in the means to diminish the ravages of the lo- 

 custs, or attempts again to labour their ruined fields. In their migrations immense 

 quantities of locusts are devoured by birds, pigs, lizards, and frogs ; and in some 

 countries in the east the inhabitants not only eat them when recent, but dry, grind 

 them, and make a kind of bread when their harvest has been deficient. At Bagdad it 

 is said the market for provisions is always lowered when locusts are in plenty. 



ORDER VI. HEMIPTERA. Rhyngota, Fab. 



Two wings covered by elytra ; mouth formed for suction, the 

 rostrum composed of a tubular articulated sheath, including 

 four scaly setae, in place of mandibles and jaws ; elytra in 

 some crustaceous, with the posterior extremity membranous ; 

 in others almost similar to wings, but more extended, thicker, 

 and coloured. 



Of all the insects furnished with elytra and wings, the Hemiptera are the only ones 

 which may be said to have neither jaws nor mandibles, properly so called. Their 

 mouth appears in the form of a cylindrical or conical jointed trunk, bent downwards 

 or extending along the breast. This rostrum has a furrow along its upper surface, 

 from which are exserted three scaly or corneous and sharp seta, which arise from 

 the inferior part of the head, immediately above the origin of the sheath, and the 

 base of which is covered by a triangular or subulate labium. This rostrum is con- 

 structed only for extracting fluid matters from plants. All these insects pass suc- 

 cessively through the different states of larva, pupa, and perfect insect ; but the 

 manner in which their metamorphosis is accomplished is different from that of the 

 Coleoptera. The larva in the present class, in place of appearing like a dull and 

 heavy worm, differs but little from the perfect insect, except in the absence of wings and 

 elytra, and being of a smaller size. Some are found in the waters, others at its sur- 

 face, while others, feeding on vegetable substances, are only found on plants. 



SECTION I. HETEROFTERA. Hemiptera, Leach. 



Rostrum attached to the anterior extremity of the head ; elytra 

 and wings horizontal, terminated abruptly by a membranous 

 appendage. 



The metamorphosis in this section is always incomplete ; the antennas have never 

 more than five joints ; their number is generally four. The first segment of the 

 thorax seen from above is much larger than the two other segments. They are ge- 

 nerally carnivorous. 



