ORTHOPTERA. ' 427 



unite in incaculable numbers and emigrate, resembling in their passag-e 

 through the air, a tliick and heavy cloud; wherever they alight all signs of 

 vegetation quickly disappear, and a desert is speedily created. Their 

 death frequently forms another scoui-ge, 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 



jx. migratorius. Length two inches and a half; usually green, with ob- 

 scure 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., ai'e frequently devastated in 

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



ORDER VII. 



HEMlPTERA.(l) 



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 maxillas pro- 

 perly so called. A tubular, articulated, cylindrical, or conical ap- 

 pendage curved inferiorlj, 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 protruded three 

 rigid, scaly, extremely fine, and pointed setas, covered at base by a 

 ligula. These sets, 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 infe- 

 rior seta consists of two filaments which are united into one at a 



(I) Half-winged, the Ryngota, Fab. 



