Studies of fluctuations in insect populations II The infestation of Meadow Foxtail Grass (Alopecurus pratensis) by the Gall Midge Dasyneura alopecuri (Reuter) (Cecidomyidae)

1. This is the second of a series of papers in which the fluctuations of insect populations in the field are being studied. 2. The degree of infestation or intensity of attack by the larvae, the degree of parasitism and the dates of emergence (host insect and its parasites) of Dasyneura alopecuri (Reuter), which prevents seed production in Meadow Foxtail grass, have received attention over a period of five years. The methods used have been fully discussed. 3. It would appear possible that reversal in the relative times of emergence of host and parasites may account for sudden changes in the degree of parasitism and, subsequently, changes in the extent of damage suffered by the crop. 4. It is desired to hold over a complete discussion of the results until similar studies on other species of gall midges have been completed.