136 AN ACCOUNT OF BRITISH FLIES. 
GENUS.— Tetragoneura, Wtz.* = praia i ies 
Body slender and elongated. Head small and round, flat above. 
Eyesround. Proboscis short. Labium short and fleshy, rigid in front — 
and hairy. Coxz elongated, femora compressed, lateral spines on 
hind tibiz. Wings longer than abdomen ; costal does not extend to 
tip of the wing. First longitudinal vein very short, third ending 
Fic. 27.—Head of 7etragoneura Sylvatica. 
before tip of wing: base of the fourth hind areolet in a transverse 
line with the base of the second, or very near the base of the wing. 
Joints of the antennz cylindrical. The larve live-in fungi and rotten 
wood. 
T. hirta, Wtz.=S. dissimilis, Zett. 
Black, clothed with whitish hairs. Thorax with grayish tinge, beset 
with large light hairs. Abdomen in ¢ dark brown with light hairs 
and somewhat shiny, ventral segment yellow; in the ? the abdomen 
is yellow, the segments have a black dorsal stripe and black bands, 
except the sixth and seventh segments, which are entirely black. 
Hypopygium yellow; ovipositor and lamelle brown. Head dark 
brown, vertex sometimes grayish ; proboscis and palpi yellow. An- 
tennze dark brown, basal and second joints yellow. Wings hyaline, 
costa dark, areolet oblong ; second and third longitudinal veins brown, 
the rest pale; the first longitudinal ending in the second before its 
middle ; fork of fourth longitudinal opposite apex of areolet ; fork 
of the fifth nearly at the base of the wing. Legs light yellow ; cox 
and tips of posterior femora dark brown, the latter has a black streak 
at the base on the ventral side; tibize and tarsi brown ; posterior 
tibia longer than metatarsus. Length 4 lin. This is a rare species. 
Haliday records it from Ireland. 
There are two other species of this genus recorded from Great 
Britain, viz., sy/vatica, Curtis, Brit. Ent., xiv., 641, 16 (1837), and 
Winnertz, Verh. d. Zool. Bot. Ges., xiii. 766. 2 (=distincta) and 
melanoceras, W\k., vide Walker, Ins. Brit., Dip., vol. iii., p. 46.t 
* Ent. Zeit. V., Stett. vii. 18 (1846). 
+ Sylvatica= Black ; proboscis, palpi and second joint of antennz yellow 
