Notes on the Timothy grass flies (Amaurosoma spp.)

Summary. 1 ?A short account of the systematic position of the Timothy flies (Amaurosoma armillatum Zett. and A. flavipes Fall.) is given and the literature concerning them is reviewed. 2 ?Their distribution is stated and notes are given on their bionomics as observed at Harpenden on material obtained from Slough, Buckinghamshire. 3 ?The parasites Microbracon exhilarator Nees and Lamprotatus sp. are recorded. 4 ?Efforts have been made to see whether the earliness or lateness of Timothy grass strain has any effect on the incidence of attack. There are indications that a dwarf strain which is an early one is less liable to attack, though this may be due to a varietal resistance rather than to the time of flowering. 5 ?It does not appear feasible to get limits of flowering wide enough to cover the period of attack, so that further investigations in this direction need not be pursued. 6 ?Indications were obtained that the effect of manuring the grass may be to lower the attack, but further work in this direction ia required.