BY FREDERICK A. A. SKUSE. 
1157 
under and close to the fourth longitudinal vein, frequently 
continuing nearly to the wing margin. Sixth longitudinal vein 
rudimentary or entirely missing. 
When the marginal cell is divided by an anterior branch of the 
second longitudinal vein the fresh cell thus formed is regarded as 
the first sub-marginal cell ; otherwise, the cell between the second 
and thii-d longitudinal veins (and the anterior branch of the 
latter) is the first, or perhaps the only, sub-marginal cell. If the 
anterior bi’anch of the third longitudinal vein be missing, one sub- 
marginal cell disappears ; and should the anterior branch of the 
fourth longitudinal vein be absent, the second posterior cell is 
merged into the first and takes its name. In the genera Trizygia 
and Azana all three anterior branches are missing, which leaves the 
wing with only one sub-marginal and one posterior cell ; in the 
case of Aphelornera the third longitudinal itself is so detached 
from the second longitudinal vein as to really make one large 
posterior cell contained by the second and fourth longitudinal 
veins. 
SECTION I. 
Sub-section I V.— M ACROCERIN^. 
Genus 6. Macrocera, Meig. 
Afacrocera, Meigen, Illig. Mag. II. 1803, p. 261 ; Macquart, S. 
a B. Dipt. I. 1834, p. 127 ; Curtis, Brit. Ent. XIV. 1837, p. 637; 
Stseger, Kr. Tidsskr. 1840, p. 230 ; Zetterstedt, Dipt. Scand. X. 
]). 4060; Walker, Ins. Brit. Dipt. III. 1856, p. 69; Winner tz, V. 
z.-b. G. Wien, XIII. 1863, p. 675 ; Geneja, Lioy, Atti. 1st. Yen. 
3* ser. t. IX, 1864, p. 229. 
Head broad, oval, flattened on the fore part. Eyes oval, a little 
emarginate on the inner side above Ocelli three, of unequal 
size, in a triangle on the front, tlie foremost one smaller. 
Palpi fonr-jointed, cylindrical, the first joint small, the following 
ones of equal length, or the fourth somewhat lengthened. 
Antennno 2- -f 1 4-joiuted, very long, frequently much longer than 
the body, projecting forwards, arcuated ; the first joint of the 
