Published online by Cambridge University Press: 10 July 2009
Detailed taxonomic studies of adult Cecidomyiidae reared from inflorescences and seed-heads of species of Gramineae and Cyperaceae during field surveys in Queensland and the Northern Territory of Australia in 1970–73 established that Contarinia sorghicola (Coq.) is restricted to non-indigenous crop and weed species of Sorghum section Sorghum that have been introduced to Australia by man and that three morphologically distinct species of Contarinia occur on native Australian grass species of Sorghum section Parasorghum. An earlier report that the wild grasses Dichanthium, Bothriochloa and Eriochloa serve as alternative hosts of C. sorghicola was not confirmed by detailed examination of long series of specimens reared from these hosts, nor was the pest species found on any other genera of Gramineae. It is therefore concluded that, in Australia, C. sorghicola has been spread (probably in contaminated seed) and maintained by grain and forage sorghums and that wild grasses are not potential sources of crop infestation. Eleven new species are described: C. roperi sp. n. and C. plumosi sp. n. from Sorghum plumosum; C. intrans sp. n. from S. intrans and S. stipoideum; C. sehimae sp. n. from Sehima nervosum; C. bothriochloae sp. n. from B. bladhii; C. dichanthii from D. annulatum var. fecundum and D. tenuiculum and possibly from D. affine and D. sericeum; C. passlowi sp. n. from D. annulatum var. fecundum; C. alloteropsidis sp. n. from Alloteropsis semialata; C. brevipalpis sp. n. from Eragrostis brownii; C. scirpi sp. n. from Scirpus lacustris and C. fimbristylis sp. n. from Fimbristylis bisumbellata. Characters of the female cerci were especially useful in diagnosing species, making it easier to identify females than males. Cecidomyiids of the genus Geromyia were reared from Setaria and cecidomyiids of the genus Lasioptera were reared from ten grass genera and one sedge genus during the surveys, but this material is not dealt with in detail. The needs for further field work and taxonomic studies are stressed and it is suggested that apertures on the dorsal surface of abdominal segment VIII in female C. sorghicola may be the openings of sex pheromone glands and would merit further detailed investigation.