362 Mr. F. W. Edwards’ Notes on British Mycetophilidae. 
S. polyzona, which is much smaller and differs in several 
details of coloration. 
Bouerina, Mg. 
In order to determine the species of this genus with 
certainty it is usually necessary to remove and mount the 
male genitalia, but some species are recognisable by other 
characters, and for these the following table is put forward. 
1. Subcostal cross-vein absent etl rE] aly Rew eee ee eres 
Subcostal cross-vein present .  . ‘ me SPA 
2. Shoulders yellow, first four Nbdamantaa segments with large 
triangular lateral yellow patches oe a reulert, Last. 
Thorax and abdomen black .  . , FMC yw os 
3. Third vein (R,) rather wavy . ; : : inermis, Ldst. 
Third vein almost straight : ; ‘ : villosa, Lndr. 
4. Fork of fifth vein (Cu) rather short [Hm palia paradoxa, sp. n. | 
Fork-cells normal ie yay MeN AN aes get lee) ae eee 
5. Thorax cinereous with three black stripes, the middle one 
divided. ges Eta G ds : é trivilta‘a, Mg. 
Thorax not distinctly dened : 5 : ere eee (8 
6. Shoulders and posterior borders of aden segments ob- 
viously yellow. «.  . - .«  basalis, Mg., 9 
Thorax and abdomen black or piabiieh ee ee Bie ys 
7. Costa produced at most one third of the distance from the apex 
of R, to that of M,+,. . , : , ‘ : eS: 
Costa produced about half the stetancs wy fag tags Sos 
8. Third and fourth antennal jointsdark .  . . lg WIkK. 
Third and fourth antennal joints yellow. .  basalis, Mg., 3. 
9. Medium-sized species; anal vein well-marked —lundbecki, Ldst. 
Small species; anal vein rather faint . .  sciarina, Staeg., 
dispecta, Dz., brevicornis, Ztt., gripha, Dz., nigricans, Dz., 
moravica, Lndr., trispinosa, sp. n., lundstroemi, Lndr. 
B. borealis, B. winnertzi, B. dubia, and B. analis are 
omitted from the above table, as I am unable to confirm 
them as British, having seen no males. 
*B. reutert, Lundstr. New Forest (D.S., C.G.L., F.J.-— 
a long series); Beattock (C.G.L.); Loch Assynt and Spey 
Bridge (J.W.Y.); Chippenham (G.H.V.—bred from rotten 
stump). I have examined 55 specimens and find that in 
only one of them is the subcostal cross-vein present. 
*B. inermis, Lundstr. Logie and Crowborough (F.J.); 
New Forest, Wells (Somerset), and Padstow (C.G.L.); 
