278 INSECTA. 
rounded emargination in the external side; in the preceding subge- 
nus it is straight(1). 
To these succeed other subgenera very analogous by the short 
form of the body, the triangular abdomen and by the antenne, 
much shorter than the head, but where the seta is simple or with- 
out very apparent hairs. 
In some, asin Eristalis, the external margin of the last external 
cell of the wings is strongly unisinuate. The body is generally 
-hairy. The antennz are closely approximated at base. 
Mattora, Meig.—£ristalis, Fab. 
Where the last joint of the antenne forms a species’of transversal 
trapezium, the widest side of which is before, and Leesentis when 
dilated an elliptical facet bordered all round(2). 
Hetopuitus, Meig.—£vistalis, Meig. Fab. 
Where the palette of the antenne forms asemioval. The body is 
generally less hairy than in the preceding subgenera. 
The body of several of the larve is terminated by a long tail, 
whence their vulgar appellation of vers @ queue de rat, or rat-tailed 
worms. They elongate and raise it perpendicularly to the surface 
of the water, or cloace in which they live, in order to respire 
through the aperture in its extremity. They are furnished inter- 
nally with two large and extremely brilliant trachez, which, near 
the origin of the tail, form numerous plexus that are constantly in 
motion. 
Reservoirs of rain-water contain numbers of these larve. Their 
tail may easily be mistaken for filaments of roots. See Réaum., Ins., 
IV, xxx: 
Hi, tenax; Musca tenaz, L.; H. abeilliforme, Réaum., Ins., IV, 
xx, 7. About the size of the male of the common Bee, and at 
the first glance resembles it in colours. The body is.brown, 
covered with fine, yellowish-grey hairs, with a black streak 
on the front; two to four fulyous-yellow spots on each side of 
the abdomen. 
(1) The E. intricarius, similis, alpinus, Meig. 
(2) See Meigen. 
