DIPT ERA. 



62 



The larva of P. tyr- 



Chiromyza, Wied., lias the antennae with five distinct joints. 



Pachyxtomux, Latr., lias the antennae 3-jointed, the third joint divided into three annuli. 

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



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

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

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

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



Xylophaous. 



Ilirmetia, Latr., has the antenna? much longer than the head, with the two first joints very short, and the third 

 very long and compressed ; the scutellum is narrowed. 



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

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



Xylophagus proper, has the body long and narrow, with the antenna: rather longer than the head, terminated 

 by a subcylindric joint. X. ater, Latr. 



Acanthomera, 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. 



Raphiurhynrhus, 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 6pines. 



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

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

 has two spines. 8. ferrughieus, 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 antenna; still more elongate, and the basal joint longer than the second ; the third 

 linear and compressed. The scutellum has two spines. 



[Ptilocera, Wied. j, (not Pttiodactyhu, u written by 1. iti, illn, has the antennas emitting three or four linear, 

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



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

 [and the abdomen very greatly dilated]. 



The third section, Stratiomydes, Latr., ha3 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 all ; and in 

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

 or six 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 terminal seta, and mostly 

 terniinated by a 2-jointed style. The BCUteUum 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 I beak. 

 Strtitiomyt proper, has the antenna.' mueh lunger than the head, the first and last joint greatly elongated j tbe 

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

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

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



winch these larva- reside. They respire by extending their 

 tails to the surface, a spiracle being situated between tin- 

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



form, serves si ■ cocoon to the inclosed papa, which, however, 



only OCCapiea nne ext remity of the larva skill. The perl 

 insert is, ape* li\ a slit made through the second segment. 



6*. ekawueUon, Fab., a very common ipi 



Odontowtfia, tfeig., have the antenna scarcely longer than 



the head, with the tiist t »n j. ii n Is shoi t, nearly equal, the thud 



forming an elongate cone, slender, with at ImbI Ore distinct 



Joints ; the last eonie, suddenly COmpit BSed, and recurved. 



BpMpphm, Latr. [CUUOaria, m.-u-j, baa the an) 



scarcely longer than the head, w ith the tWO basal joints short, 



the thud forming a shorter cone, thicker, the fourth Joint 



trim. at.- conn, mi hh -nly n. mowed at tip. and terminated by a 



2 jointed style. 8. tpMppittm FAarwcsMBat, Latr.). 



.i — S cbama leun. 



Orycera, Meig., similar to Bphippinm in the Shortness Of the antenna, which are also Btylifuoua, but with 



8 S 



