Life History.

The perfect insect (Nos. 9 and 10) is of a pale yellowish colour, with six legs. Its wings are of a light yellow. It has a remarkably long ovipositor, and its antenna; are hairy. It appears first about the second week in June and places its eggs in the ears in a somewhat remarkable manner as soon as they are put forth. The fly rests upon one of the florets of the ear and deposits its tiny yellow eggs within the sheaths or husks, hereafter to be chaff, of the corolla, and close to the embryonic grain, by means of a long tube projected from its body. The female lays from ten to twenty eggs.

The larvæ (Nos. 2 to 5) appear in about eight days. At first they are yellow. After a time they become more of an orange tint as they approach the pupa stage. At this time M. Rendu and M. Bazin state they have the power of springing to the ground from the ears, and Köllar says that they have powers of jumping.^* It is certain that the greater part of them get to the ground in some way, either by springing or falling down. They bury themselves about an inch in the soil and are then transformed into pupæ, in which state they remain until the end of April or the beginning of May, according to the circumstances of season and the general surroundings. Some of the late hatched larvae remain in the ears of corn by the hardening of the chaff, in ripening. These are carried with the corn into ricks and barns and are thrashed out with the wheat, and if they are placed afterwards in suitable conditions they turn to pupæ and produce flies in due time. The larvæ have great vitality, and though they may seem to be quite dried up and dead they will revive upon being placed in water. In 1881 upon taking in a wheat stack enormous quantities of these larvæ were found in the chaff, and a good deal of the corn was thin and light. There must have been as many as six gallons of the larvae in the box under the "seed" sieve of the thrashing machine. In the early summer numbers of tiny flies, or midges, may be seen hovering over any lumps of chaff, or "cavings," that may have been left in rick-yards or places where corn has been thrashed in the fields. It is supposed that pairing takes place directly the flies come from the pupæ.

It has been thought by some entomologists that the Cecidomyia on first emerging from the pupa stage lays eggs in various grasses, and that it is the broods from these which infest the wheat. Though this has not been proved, it is most probable that two or more broods arc produced in each season.