On the 5th of July, a friend brought me a very remarkable Larva that he found in a field the previous evening, and which had attracted his attention by the light it emitted. When alive it was about an inch and a half in length, and 0.25 inch in width across the middle, its general appearance being long and narrow; it is flattened above, and composed of twelve segments (exclusive of the head); each segment is broad and cut squarely, and overlaps the following one, the posterior angles being a little acute ; the anterior segment is gradually narrowed in front and rectilineally truncate, forming a shield to the head which is retractile within it ; each of the first three segments has a pair of claw-like legs attached to it beneath. The general colour of the insect is a dark drab, the posterior angles of each segment, the softer connecting portion between the segments, and the under side of the body being much paler, and of a somewhat dirty yellow hue; on each side there is a deeply impressed line in which the spiracles are situated.