102 
Psyche 
[September 
Posterior orbits much shorter than the greatest width of 
the inner orbits; occipital margins of posterior orbits 
and of postvertex scarcely produced and separated by 
shallow curves 4. 
3. Occipital margin of postvertex somewhat more produced 
behind than the posterior orbits. Third longitudinal 
vein (R 4+5 ) setulose throughout. Cross-vein closing 
second basal cell very oblique, the upper outer angle of 
the cell acute 0. spinifera (Leach). 
Occipital margins of postvertex and of posterior orbits 
about equally produced behind. Third longitudinal vein 
either bare or at most with a few setae toward apex. 
Cross-vein closing second basal cell nearly vertical, the 
upper outer angle of the cell almost square. 
A. erythropsis Bigot. 
4. Second basal cell (M) very short; second section of 
fourth longitudinal vein (Mi + 2 ) about twice as long as 
first section of fifth (M 3 + Cui) . Frons not or hardly 
wider than an eye. Postvertex not divided by a trans- 
verse depression from the lower, frontal area. Third 
longitudinal vein (R 4+5 ) with minute setae, as a rule on 
apical portion only * 0. bisulcata Macquart. 
Second basal cell long; second section of fourth longi- 
tudinal vein at most one and one-third times the length 
of the first section of the fifth (often about the same 
length) 5 
5. Third longitudinal vein (R 4+5 ) distinctly setulose 
throughout. Postvertex not divided by a transverse de- 
pression from the lower, frontal area. Frons narrow, 
not or hardly wider than an eye 
0. fumipennis (Sahlberg). 
Third longitudinal vein bare or at most with a few min- 
ute setae cn apical portion 6. 
6. Postvertex not divided by a transverse depression from 
the lower, frontal area, extending as one smooth and 
shiny plate from the occiput to the fronto-clypeus. Frons 
at least one and one-third times as wide as an eye. Wing 
7 to 9 mm. long 0. fossulatct Macquart. 
