DIPTERA. 
627 
Chiromyza, Wied., has the antennae with five distinct joints. 
Pachystomus, Latr., has the antennae 3-jointed, the third joint divided into three annuli. The larva of P. syr- 
phoides, 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 antennae 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 antennae 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. 
RapMorhynchus, 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 siz^j and inhabit South America. 
The others have the scutellum armed with spines. 
Ccenomyia, Latr. {Sicus, Fabr.), are closely allied to the two preceding subgenera ; the antenna; 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. 
Bens, 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.J, (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 antennae 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 antennte 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 
I those which do not possess it the third joint is long, elongate-fusiform, and 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 
! Strati OMYS, Geoff. 
I Some have the third joint of the antennae elongate, fusiform, or conical, without a terminal 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, 
j proper, has the antennae much longer than the head, the first and last joint greatly elongated ; the 
J 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 larvae 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 second segment. 
S. chamaeleon, Fab., a very common species. 
Odontomyia, 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 distinct 
joints ; the last conic, suddenly compressed, and recurved. 
Ephippium, 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-jointed style. S. ephippium, Fab. (E. thoracicum, Latr.). 
Oxycero, Meig., simitar to Ephippium in the shortness of the antennae, which are also styliferous, but with 
S S 2 
