Order 12. 



DIPTERA. 



627 



The lai-va of P. syr- 



Chlromyza, Wied., lias the antenna: v.'ith five aislinct joints. 



Pachystomus, Latr., has llie antennai 3-jointed, the third joint divided into tln'ee annuli, 

 pkoides, Pz., lives beneath the bark of the pine; its pupa resembles that of the Tabani. 



The second section, Decatoma, Latr., has the antennae always composed of three joints, the last 

 being longer, without a style or seta, and divided into eight annuli, clavate in some, and nearly 

 cylindric, or elongate-conic in others. The wings are generally incumbent on the body, and the tarsi 

 have three pulvilli. They may be united into a single genus — 



Xylophagus, 



Hermetia, Latr., has the antennae much longer than the head, with the two first joints very short, and the third 

 very long and compressed ; the scutellum is narrowed. 



The antennas in the others are never much longer than the head, and terminated by a nearly cylindric, or 

 elongate-conic joint. Some have the scutellum not spined. 



Xylophagus proper, has the body long and narrow, -with the antenniE rather longer than the head, terminated 

 by a subcylindric joint. X. ater, Latr. 



Acanthoviera, Wied., has the antennae at least as long as the head, and terminated by a joint in the form of an 

 elongate cone ; the first joint larger than the others; the abdomen broad and flattened; the face with a pointed 

 beak ; the two joints of the palpi of equal size. 



Raphiorhynchus, Wied., has the basal joint of the palpi very short, and the second much longer, and terminated 

 in a point. The species of this and the preceding are of large size, and inhabit South America. 



The others have the scutellum armed with spines. 



Canomyia, Latr. (Sicus, Fabr.), are closely allied to the two preceding subgenera ; the antennae scarcely longer 

 than the head ; the palpi very visible, cylindric, pointed at the tip, with two equal-sized joints. The scutellum 

 has two spines. S. ferrugineus, Fab. 



Beris, Latr., has the antennae rather longer than the head, with the two basal joints of equal size, and the third 

 elongate-conic. The scutellum has four or six spines. 



Cyphomyia, Wied., has the antennae still more elongate, and the basal joint longer than the second ; the third 

 linear and compressed. The scutellum has two spines. 



[Ptilocera, Wied.], (not Ptilodactylus, as written by Latreille), has the antennae emitting three or four linear, 

 villose filaments, the tips being nearly setaceous. The scutellum has four teeth. 



Platyna, Wied., has the antennas filiform ; the two basal joints elongate-cylindric ; the scutellum with one spine, 

 [and the abdomen very greatly dilated]. 



The third section, Stratiomydes, Latr., has also the antennae 3-jointed, the last joint offering not 

 more than five or six annuli, the style, or seta, not included. The latter exists in nearly aU ; and in 

 those which do not possess it the third joint is long, elongate-fusiform, and always divided into five 

 or sis joints ; the wings are always incumbent upon each other. In some of the species, which have 

 the antennae terminated by an oval or globular mass, and always aristate, the scutellum is not spined. 

 This section corresponds with the genus 



Stratiomys, Geoff. 

 Some have the third joint of the antennae elongate, fusiform, or conical, without a teiminal seta, and mostly 

 terminated by a 2-jointed style. The scutellum armed with two teeth, or spines, in the majority. 

 In the four following subgenera the proboscis is short, and the front of the head does not form a beak. 

 JS</■a^^on^J/s proper, has the antennae much longer than the head, the first and last joint greatly elongated; the 

 last with at least five distinct joints, without a sudden style at the tip. The larvae have the body long, flat, cori- 

 aceous, and annulose ; the three terminal joints, long and slender, form a tail, terminated by a coronet of hairs ; 

 the head is scaly, small, oblong, and furnished with a number of small hooks, serving to disturb the water, in 



which these larvee reside. They respire by extending their 

 tails to the surface, a spiracle being situated between the 

 scales, at the extremity of the body. The skin, unchanged in 

 form, serves as a cocoon to the inclosed pupa, which, however, 

 only occupies one extremity of the larva skin. The perfect 

 insect escapes by a slit made through the spcond segment. 

 S. chamceleon, Fab., a very common species. 

 Oduiitomyia, Meig., have the antennae scarcely longer than 

 the head, with the first two joints short, nearly equal, the third 

 forming an elongate cone, slender, with at least five distmct 

 joints ; the last conic, suddenly compressed, and recurved. 



Ep/iijipium, Latr. (Clitellaria, Meig.), has the antennae 

 scarcely longer than the head, with the two basal joints short, 

 the third forming a shorter cone, thicker, the fourth joint 

 truncate-conic, suddenly narrowed at tip, and terminated by a 

 2-joiutcd style. tS. cp/iippium. Fab. (E. 1/ioiaciciim, Latr.). 

 Oxycera, Meig., similar to Ej>hippium in the sliortness of the antenna-, which are also styliferous, hut with 



Vig. lo5. — S clmiuaileon. 



