214 Mr. F. W. Edwards on British Limnobiidae. 
1. Blackish species - ; : 4 ; 2 
Yellow or light brown species (at least the thorax) . Ses 
2. Thorax shining black. : ; ; ; , ay eee 
Thorax dull blackish or dark brown ; ; : 3 ia 
3. Wings short and functionless in both sexes : . alter Mg. 
Wings normal : : bihamatus Meij. 
4. Whole body densely elothed’ sib long hair, also the wing- 
membrane, thorax dark brown, somewhat shining murinus Mg. 
Body short-haired (normal); wing-membrane bare, thorax 
dull blackish-brown . ; : . obscurus Mg. 
5. Very small species; cross-vein 7 ie than twice its own length 
from the base of R,; Ax ending before fork of Cu; wing- 
fringe on basal half of lower margin longer than the breadth 
of the cubital and two anal cells; legs pale . pusillus sp. n. 
Larger; cross-vein r generally 3 times its own length from the 
base of R,, often more; Ax ending beyond fork of Cu; wing- 
fringe shorter; legs darkened except towards base of femora 6. 
6. Thorax brown; head black or grey; wing-hair dark . 
bifilatus Verr.;* curvatus Tonn.; “occultus Meij.; gladius 
Meij.; bifidus Goet. 
Thorax yellow (sometimes slightly brownish-tinged) . Ay we 
7. Wing-hair yellow or pale, at least in large part; head and 
abdomen yellow , \, : 
appendiculatus Staeg. ; ane Meij. ; Re Meij. Wing 
hair alldark ; . : : . ; sve: 
8. Head pale. : , : : ; “ pleuralis Meij. 
Head dark grey on vertex ; ; . 9. 
9. Abdomen orange-yellow \ ochraceus Mg.’ fla vus Goet. 
Abdomen more or less darkened  propinguus Egg.; cinereifrons 
Meij. 
M. pusillus sp. n. 
A very small species, allied to MW. murinus Mg., in venation, but 
much less hairy, and of a brownish-yellow coloration; halteres pale. 
Head, including palpi and antennae, blackish. Joints of flagellum 
sub-cylindrical, narrowed a little at each end, twice as long as broad, 
apical joints gradually becoming smaller; verticils nearly three 
times as long as each joint. Thorax uniformly dingy ochreous or 
brownish-yellow, slightly shining; praescutum with two rows of 
long brown hairs; a few similar hairs on the scutum, Abdomen 
(except for the last segment and the ovipositor) somewhat darker 
than the thorax, with shorter but denser hair. Legs rather pale 
ochreous, only the tarsi somewhat darker; hairs of femora about 
twice as long as the diameter of the legs. Wings with long dense 
