G24 



INSECTA. 



Stygides, wide apart, terminated by an awl-shaped joint ; the proboscis is ordinarily very short, scarcely 

 advanced in front of the head, often received into the oral cavity, and terminated by a small thickened 

 part formed of the lips. The palpi are generally hidden, filiform, and each is attached to one of the 

 seta? of the rostrum. The abdomen is squarer than in Bombylius. These insects are generally very 

 hairy. Their habits are very similar to those Diptera. They often alight on the ground, upon walls 

 exposed to the sun, along which they are often observed flying, as well as upon leaves. 



Stygides, Latr. (Lomatia, Enc. Me'th., Styyia, Meig.), has the antennae wide apart at the base. 



In all the others they are wide apart at the base. 



Some of these have the head subglobose, with the proboscis short, and the extremity of the wings not 

 retioulated. 



Anthrax preper, with the ocelli contiguous ; [a very numerous genus, having the wings generally spotted]. 



Ilirmoneura, Wied., with the anterior ocellus at a distance from the other two, and the proboscis retracted. 



The others have the head shorter, subhemispherical, the proboscis longer than the head, and the extremity of 

 the wings often strongly reticulated. 



Mulio, Latr., has the wings reticulated in the usual manner, and the proboscis but little longer than the head. 



Nemestrhia, Latr. (Cytherea, Fabr.), has the extremity of the wings reticulated, as in the Neuroptera, and the 

 proboscis much longer than the head ; the two basal joints of the antennae very nearly equal, and the last very short 

 and conical ; the tarsi have three pulvilli. 



Fallenia, Meig., is formed of two species of Nemestrina, which scarcely differ from Anthrax in the reticulation 

 of the wings. 



Colax, Wied., also appears to us to approach the terminal Anthracii in the antennae and wings, but the oral 

 cavity is closed, as in (Estrus, and the ocelli are wanting. 



Our second general division of the Tanystoma has the probosois membranous, with the basal part 

 generally very short, terminated by two lips, very distinct, and ascending. The larvae of the terminal 

 Diptera of this division have the head of a variable form. 



Some of these (Leptides) have the wings extending, and exhibiting many complete cells ; the 

 antennae do not terminate in a plate, and the palpi are filiform or conical. 



Thereva, Latr. (Bibio, Fab.), has the palpi withdrawn into the oral cavity ; the antennae are fusiform or elongate- 

 conic at the tips, with a small articulated terminal style. Type, Bibio plebeia, Fab., which is found on plants. 

 The larva of T. hirta, De Geer, lives in the earth, and resembles a small Serpent ; its body is white, and pointed 

 at each end. It entirely strips off its skin on assuming the pupa state. 



In the others the palpi are exterior, and the last joint of the antennae is either globose or kidney-shaped, ovoid 

 or conic, and terminated in all by a long seta. The tarsi have three pulvilli. Such is 



Lettis, — 

 Which is divided into numerous subgenera. 



Atherijc, Meig., has the basal joint of the antennae larger than the second ; thick, at least in one sex, and with 

 the third joint lenticular and transverse ; the palpi are porrected, 



Leptis, Fab., formerly Rhayio, Fab., has the terminal joint of the antennae subglobose, or ovoid, always termi- 

 nated in a point, and never transverse. In Leptis, Macquart, the antennae are shorter than the head, with the 

 three joints nearly equal in size, and the palpi porrected. Type, Musca scolnpacea, Linn., a very common species. 



Chrysopilus, Macq., differs from the last in having the palpi perpendicularly elevated. 



[Vermileo, Macq.], has the antennae as long as the head, with the first joint cylindric, the second short, the third 

 conical, and the palpi recurved. Type, Musca Vermileo, Linn. [Vermileo De Geeri, Macq., a species common in 

 France, but not discovered in England]. The larva is cylindrical, with the front of the head attenuated, and four 

 fleshy lobes at the other end of the body. It gives to its body all kinds of curvatures, crawling on the sand, in 

 which it forms a conical burrow, at the bottom of which it conceals itself, either entirely or only in part, suddenly 

 starting when an insect falls into the hole, and twisting itself round it, thrusting the hooks of its head into its 

 body and sucking its juices. It then throws the carcase away, as well as the sand, by curving its body into an 

 arch, and then suddenly letting it go. The pupa is concealed beneath a layer of sand. I have kept some of these 

 larvae, sent me by M. de Romaud, for nearly three years unchanged. 



Clinocera, Meig., from its wings, appears to belong to the next division. 



The other Tanystoma of our second division have the wings incumbent on the body, and only exhibit 

 two complete or closed cells. The antennae terminate in a palette, nearly always furnished with a seta. 

 The palpi, in the majority, are flattened, and rest on the proboscis. 



These characters, a compressed body, triangular head, slightly advanced like a muzzle ; the abdomen 

 curved beneath, and long slender legs armed with spines, particularly distinguish the genus 



Dolichopus, Fab., Latr., — 

 Which now forms a small tribe, distributed by Macquart in a very natural manner, which we have 

 adopted, except in reversing it, whereby Orthochile is brought to the head. 



