figures in the following columns represent the percentage that grew. One-half of the seed was planted one-eighth of an inch deep and one-half at one inch deep. The first column of figures represents the former or shallow planting, the second column the latter or deeper planting.

These experiments were conducted in the college green-house, under the most favorable conditions of soil, temperature, and moisture.

THE BLACK WHEAT-STALK ISOSOMA.

ISOSOMA NIGRUM, n. sp.-Early last autumn I received from Mr. Wm. Deyo, of Denton, Wayne county, Michigan, specimens of wheat straw which contained from five to sixteen larvæ of a four-winged (hymenopterous) fly. The portion attacked was usually near a joint, but might be anywhere along the internode, and was found above every joint, though very rarely above the highest one. The immediate region of attack was creased and deformed (Fig. 1), though not swollen, and was very hard, so

Fig. 1.-Black dots show exit of fly.

that to cut it, except with a very sharp knife, was difficult. At this portion of the stalk, which was usually from three centimeters (one and a-fifth inch) to five