^56 INSECTA. 



Some species of the following subgenus, such as the Gryllus can- 

 ■natus of Linnaeus, and the G. gal/inaceus of Fabricius, are interme- 

 diate, by their antenna?, between Truxalis and Acrydium proper, and 

 form the genus Xiphicera, Lat. — Pamphagus, Thunb. 



AcRYDiuji proper: — Gryllus, Fab. — Gryllus locusta, and some 



G. BULLA, Li7l. 



The true Acrydia differ from the Pneumorse in their posterior 

 legs, which are longer than the body, and in their solid, non-vesicular 

 abdomen, and from the Truxales in their ovoid head, and tlieir an- 

 tennse, which are filiform or terminated by a button *. 

 They fly by starts, and to a considerable height. 

 The wings are frequently very prettily coloured, particularly with 

 red and blue, as observed in several species that inhabit France. 

 The thorax, in some of those that are foreign to Europe, frequently 

 exhibits crests and large v.'arts, in a word, a singular variety of 

 forms. 



Certain species, called by travellers Migratory Locusts, sometimes 

 unite in incalculable numbers and emigrate, resembling, in their pas- 

 sage through the air, a thick and heavy cloud; wherever they alight 

 all signs of vegetation quickly disappear, and a desert is speedily 

 created. 'I'heir 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 in- 

 habitants collect them for their own use and for com:nerce. They 

 take away their elytra and wings and preserve them in brine. 

 A considerable part of Europe is frequently devastated by the 



A. migraiorius ; Gryllus migratorius, h.; Rces. ; Insect, II, 

 Gryl., xxiv. 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 P'urope, Barbary, Egypt, &c., are frequently 

 devastated in like manner by other species, some of which are 

 rather larger — G. cegyplius, tartaricus, L., — which dififer b\it 

 little from the Gryllus lineolus of Fabricius, found in the south 

 of France — Herbst., Archiv. Insect., LIV, 2, — a species proper 

 to the same countries, and which is the one that is prepared 



Herbst., lb., vii, 7, the mule ; 6, the female ; Stoll, viii, b. 27 — Druiy, Insects, II, 

 xl, 1. 



* In many species, on each side, and near the origin of the abdomen, is a large 

 cavity, closed internally by a very thin membranous diaphragm, coloured like nacre. 

 I have described this organ (Mi^moires du Museum d'Histoire Naturelle, VI U), 

 which must necessarily have some influence on the stridulous noise of these Insects, 

 as well as on their flight. I have compared it to a sort of drum. 



