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Show 44 INSECTA. of the abdomen a 1m os t wholly or. for the greater part, and the elytra form an elongated and arched triangle~ 1 )· DooYDIUM, Lat. Where the elytra are wholly or :ostly ::i~;e:~r~:~p::~e:::::~ scutellar prolongation of the prot orax less lanceolate or spinif~:~~~·is at least partially exposed, although In the others, the scu lon ed. the posterior extremity of the pro-the prothorax may be pro g t' which distinguishes it from the thorax presents a transverse su ure, scutellum. CENTROTus, Fab. Such are the I G C cornutus· Cicada cornuta, L ; Panz., Faun. nsect. erm., L 1 ~- Leng~h four lines; thorax furnished with a horn on each side, and prolonged posteriorly into a point as long as the abdomen.- In the woods on Filices and other plants. 0. genistre, Fab.; Panz., lb., 20. But half the ~ize of the cornutus, with its thorax simply prolonged poster1orly.-On the Genistre(3). · . We will now pass to those species in which the he.ad IS scarcely lower than the prothorax, or is level with it, and horizontal ~r b~t slightly inclined when seen from above; where th~ prothorax IS net· ther raised in the middle nor prolonged posteriorly, and at most only presents lateral dilatations; and where the mesothorax has the form of an ordinary sized and triangular scutellum. The elytra are always entirely exposed, and the posterior tibire at least, always spinous. . In several, such as the followiog, the thorax has the fig.ure of an irregular hexagon; it is prolonged and narrowed posteriorly, and terminates by a truncation, so as to serve as a point d'appui to the base of the scutellum, and even frequently receiving it, this trun· cated part being concave or emarginated. .lETALioN, Lat. -JEt alia, Germ. The Insects of this subgenus are distinguished from those of other ( 1) See Fab., Syst. Ryngot. (2) The Oentrotus horridua, triji.dus, globularia, clavatua, claviger, Fab. (3) The 0. comutua, acutellaris, &c., Fab. IIE~U J1TERA. 45 subgenera of the same division by several characters. The head, viewed ft·om above, merely presents a transversal edge; the front is abt·uptly inclined, and the ocelli are situated thet·e between the ordinary eyes, and consequently inferiorly. The antennre, very small and distant from these latter organs, are inserted beneath an ideal line drawn from one to the other. The space immediately under the front is flattened and smooth. The tibire are neither ciliated nor dentated( 1). In the three succeeding subgenera, the vertex is triangular and bears the ocelli. The antcnnre at·e inserted in an ideal line drawn f1·om one ordinary eye to the other or above it. LEDRA, Fab. Where the head is much flattened before the eyes, in the form of a transversal clypeus', arcuated, ami terminated in the middle of the anterior margin by an obtuse angle·. All the under part of the head is plane or on a ]evel. The sides of. the prothorax project in the manner of horns rounded at the extremity, or of pinions. The posterior tibire are strong.ly compressed and as if bordered externally by a dentated membrane. The · L. aurita; Oicacla aurita, L.; Oigale Grand-Diable, Geoff., belongs to this subgenus(2). Crocus, Lat. Where the antennre terminate directly after the second joint in a ( 1) Lat., Consid.: sur l'Ord. des Crust. des Arach. et des Insect. and the Zool., and Anat. of MM. Humboldt and Bonpland. See Germar, Magas. der Entom., rv,p.94. · (2) See Fab., Syst. Ryngot., and Lat., Gencr. Crust. et Insect., llJ, p. 157. See also Encyc. Method., Insect, X, 600, article Tcttigone, and also Tettig~nides, Ib., where the editors, Messrs Lepeletier and Serville, offer some new considerations and establish new genera, but with which I was unacquainted until I had tet•minated my work on this family, and consequently had no time to verify, on the Insects themselves, the characters which they assign to those sections. I will restrict my. self to the following remark. The desc•·ipticin of the Eurymele fenestree exactly agrees with a species figured by Donovan, in his splendid work on the Insects of New Holland, and consequently the editors of the article in question must have been deceived as to the habil'\t o( this Insect, which they say is from Brazil. In case this synonyme be correct, the distinctive character of this new genus, the absence of simple eyes, would be false, for they exist on the superior part of the front, although, at first, they are not easily perceived. This species would then re-enter t~e subgenus Jas8U8. |
