398 INSECTA. 



air, a thick and heavy cloud ; wherever they alight all signs of vegetation 

 quickly disappear, and a desert is speedily created. Their death frequently 

 forms another scourge, as the air becomes poisoned by the frightful mass of 

 their decomposing bodies. 



M. Miot, in his excellent translation of Herodotus, has given it as his 

 opinion, that the heaps of bodies of winged serpents which that historian states 

 he saw in Egypt, were nothing more than masses of this species of Acrydium. 

 In this I perfectly agree with him. 



These insects are eaten in various parts of Africa, where the inhabitants 

 collect them for their own use and for commerce. They take away their 

 elytra and wings and preserve them in brine. 



A considerable part of Europe is frequently devastated by the 



A. migratorius. Length two inches and a half; usually green, with obscure 

 spots; elytra light brown spotted with black ; a low crest on the thorax. The 

 eggs are enveloped in a frothy and glutinous flesh-coloured matter, forming a 

 cocoon, which the insect is said to glue to some plant. Common in Poland. 



The south of Europe, Barbary, Egypt, &c., are frequently devastated in like 

 manner by other species, some of which are rather larger. 



ORDER VII. 



HEMIPTERA*. 



THE Hemiptera, according to our system, terminate the numerous division 

 of insects which are provided with elytra, and of all those, 

 are the only ones which have neither mandibles nor 

 maxillje properly so called. A tubular, articulated, cylin- 

 drical, or conical appendage curved inferiorly, or directed 

 along the pectus, having the appearance of a kind of rostrum, presents along 

 its superior surface, when raised, a groove or canal from which may be pro- 

 truded three rigid, scaly, extremely fine, and pointed setae, covered at base by 

 a ligula. These set, when united, form a sucker resembling a sting, sheathed 

 in the tubular apparatus we have just described, where it is kept in situ by the 

 superior ligula placed at its base. The inferior seta consists of two filaments 

 which are united into one at a little distance from their origin, so that in reality 

 the sucker is composed of four pieces. 



The mouth of Hemipterous insects is only adapted for extracting fluids by 

 suction ; the attenuated stylets of which the sucker is formed, pierce the 

 vessels of plants and animals, and the nutritious fluid, being successively com- 



* Half-winsred, the ni/ntjota, Fabriciu*. 



