The Book of the Fly / A nature study of the house-fly and its kin, the fly plague and a cure - George Hurlstone Hardy

3 (4). Vein endings round the margin (plate IV, figs. 1, 2, 3) not more than 6.

Cecidomyidæ, II

4 (3). Vein endings more than 6.

5 (20). Thorax (plate VI, 31) without B, I, 8 conspicuous.

6 (15). Costa ending at apex of wing (plate IV, 4-11).

7 (12). Ocelli as in plate I, or as in plates VI, I and II, 4.

8 (9). Discal cell (O, 4b or O, 5²) present (plate IV, 16).

Rhyphidæ, XIV

9 (8). Discal cell absent (plate IV, 4-7).

10 (11). Antennæ long (plate II, 3-6); or, if short, coxæ elongated.