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Show 256 INSECTA. mate to the last mentioned Anthraces, but according to that gentleman the oral cavit.y is closed as in (Estrus, and the ocelli are want-ing. Our second general division of the Tanystoma is characterized by a membranous proboscis, usually with a short stem, projecting but slightly and terminated by two very distinct and raised or ascending lips. The form of the head in the larvre of the last Diptera of this division is variable; In some-Leptides-the wings are distant and exhibit se-veral complete cells. The antennre are not terminated en pafette. The palpi are filiform or conical. Sometimes these palpi are withdrawn into the oral cavity. The antennre have a fusiform terp1ination or one resembling an elongated cone, with a little articulated stilet at the end(l ). THEREVA, Lat. Meig.-Bibio, Fab. To which belongs the following species. · T. plebeia; Bibio plebeia, Fab. Black, with cinereous hairs; abdominal annuli margined· with white. On plants. The larva of a species of this genus-Nemotelua !tirtus, De Geer-lives in the ground and resembles a little serpent. Its body is white and pointed at both ends. It changes the whole of its skin when about to become a pupa(2). Sometimes the pal pi are exterior. The last joint of the antennre is either almost globular or reniform, or nearly ovoid or conical and terminated by a long seta. The tarsi are furnished with three pellets. They form the genus (1) This subdivision corresponds to the family of the Xylotoma of Messrs Meigen and Macquart. (2) Lat., Ibid., Fab., Meig. and Macquart. In the collection of Faujas, I SAW l piece of schist that exhibited the impression of a. species of this genus. DIPTERA. 257 LEPTIS. Which·1 8 d1' V1'd ed into several su b genera. ATHERix, Meig. Fab. Where the first J. oint of th th 1. c k at least in one of th e antennre ' 1a rger t h an the second is transversal. e sexes' and th e t h1' rd 1. s lenticular a' nd The pal pi project( 1 ). LEPTis, Fab. Meig.-olim Rhagio, Fab. Where the last joint of th always terminated in a point ~a a~tennre is almost globular or avoid, In some th ' n never transversal. . . ' e antennre are shorter th JOmts are nearly of equal length. an the head, and their three Here, the palpi project. Such are the Leptia M is avoid or pyriform. ' acq., where the third joint of the antennre L. acolopacea; Muaca acolo ace Geer, Insect., VI ix 6 Th 'P a, L.; Nemoteze becaaae De ' ' · orax black· bd ' a range of black spots an th b k ' a amen fulvous, with lated with brown. Ver c e ac ! legs yellow; wings macu- There, the palpi are ra' dy o~mon lD woods. th . lse vertically f, • at naturalist, and united to .B.the . b' ormmg the Ohryaophilua of In the others, the ante rzx Y Fabricius. 1 nnre are as 1 e ongate~ and cylindrical, the secon~ngh as the head, the first joint ~he palp1 are turned up. The .. s or.t, and the third conical· mg subgenera •. The abdomen f.o:i~;~~~ thicker than in the preced: ~· vermzleo; Muaca vermileo L. , ' Ibid., x. Resembling a Ti ul' •. , Nemotele ver-lion, De Geer the thorax; the abdomen efo a, yellow! four black streaks o~ spots; wings immaculate. ngated, Wlth five ranges of black The larva·IS a 1m ast cylindrical· . th.e smallest, and there are ~1 our ma'nItds'b al nterior portion is m uc h mlty. It resembles a stick-like 1 es on the opposite extre-equally rigid when withd rawn ~ geo~etra (caterpillar) and . 1ram lts d aml.c.l1 • It b'e nds itIss (1) See the works juat quoted. VoL. IV.-2 H |