HOVER-FLIES IN ESSEX 103 Clapham, A. R., Tutin, T. G., and Warburg, E. F. (1968). Excursion Flora of the British Isles, edition 2. Cambridge. Coe, R. L. (1953). Diptera, Syrphidae. Handb. Ident. Brit. Ins. 10: (pt 2). Collin, J. E. (1952). On the subdivisions of the genus Pipizella Rnd., and an additional British species (Diptera, Syrphidae). J. Soc. Brit. Ent. 4: 85-88. Colyer, C. N., and Hammond, C. O. (1951). Flies of the British Isles. Warnes, London. Curtis, J. (1832). British Entomology 9: 432. Griffiths, G. C. D. (1954). On gynandromorphs in Melanostoma ambiguum (Fallen) (Diptera, Syrphidae). Entomologist 87: 136-139. Harris, M. (1776). An Exposition of British Insects. London. Harwood, W. H. (1903). Insecta. The Victoria History of the County of Essex 1. London. Huggins, H. C. (1957). Volucella zonaria in Essex. Essex Nat. 30: 72. Jennings, F. B. (1929). Brachypalpus bimaculatus Mcq. in Epping Forest. Ent. mon. Mag. 40: 160-161. Meikle, R. D. (1969). Garden Flowers. London. Parmenter, L. (1952). Flies visiting Greater Stitchwort, Stellaria holostea Lunin. (Caryophyllaceae). J. Soc. Brit. Ent. 4: 88-89. Parmenter, L. (1953). Some spiders and their prey. Ent. mon. Mag. 89: 135. Payne, R. M. (1968). Hover-flies in an Essex garden. Essex Nat. 32: 161-163. Payne, R. M. (1973). Some uncommon Syrphidae (Dipt.) in Essex. Ent. mon. Mag. 108: 165. Pedersen, E. T. (1972). The Danish species of the genus Paragus Latr. (Diptera, Syrphidae). Flora og Fauna 78: 1-6. Pratt, C. B. (1951). A fly new to Essex. Essex Nat. 28: 299. Shillito, J. F. (1947). Pocota personata (Harris, M.) (Diptera, Syrphidae) from Epping Forest. Ent. mon. Mag. 83: 180-181. Shillito, J. F. (1948). Notes on insects visiting diseased elms. Ent. mon. Mag. 83: 290-292. Speight, M. (1973). British species of Sphaerophoria (Dipt. Syrphidae) confused with S. menthastri (L.). Entomologist 106: 228-233. Thompson, A. T. (1960). Proc. R. ent. Soc. Lond. (series C) 25: 26-27. Verrall, G. H. (1901). British Flies 8. London. Vockeroth, J. R. (1969). A revision of the genera of the Syrphini (Diptera: Syrphidae). Memoirs of the Entom. Soc. Canada 62. Ottawa.