21 (22). V, 6 absent (plate IV, 15).
Ptychopteridæ, XI
22 (21). V, 6 present.
23 (24). V, 1a ending in costa and (plate IV, 17-22) united to V, 1b by X, 1b; last joint of palpi (plate VI, 4) never whip-like.
Limnobidæ, XII
24 (23). V, 1a ending in V, 1b; and, except for X, 1a at its base, not united by X (plate IV, 23-26); palpi (plate VI, 5).
Tipulidæ, XIII
25 (2). Antennæ short, 3-jointed (plate III); 3rd joint sometimes ringed.
BRACHYCERA (short-horns)—
26 (140). Wing veining normal; X-veins present.