\5^ THE GENUS THEOBALDIA (DIPTERA, CULICIDAE) IN VICTORIA By N. V. DOBROTWORSKY, Georgina Sweet Fellow, in Economic Entomology. Zoology Department, University of Melbourne. (Nine Text-figures.) [Read 30;h June, 19.54.] fAA*S. Synopsis. Three species of the genus Theobaldia, T. frenclii Edw., T. hilli Edw., and T. inconspicua Lee have been previously recorded from Victoria. To this list are now added T. Uttleri Taylor, T. victoriensis, n. sp., and T. frenclii atritarsalis, n. subsp. The adults of T. hilli, T. frenclii and T. Uttleri are redescribed and descriptions are given of the previously unknown immature stages of these species. On the basis of the structure of the larvae, T. victoriensis, n. sp., is placed in the subgenus Culicella. For T. hilli Edw. and T. frenclii Edw., a new subgenus, Neotheohaldia, and for T. Uttleri Taylor a new subgenus, Anstrotlieoialdiciy are proposed. An account is given of the biology of the Victorian species of Theobaldia. Introduction. Mosquitoes of the genus Theobaldia are widely distributed in the northern hemi-sphere mainly in temperate regions; a few species extend into the tropics in Africa and North America. In the southern hemisphere the genus is represented only by two species in Africa, one in New Zealand and seven in Australia. The six species hitherto known from Australia are: T. atra Lee, from "Western Australia, T. inconspicua Lee, from New South Wales and Victoria, T. hilli Edw. and T. frenchi Edw., from Victoria, T. weindorferi Edw., from Tasmania, and T. Uttleri Taylor, from Tasmania and New South Wales. The original descriptions of these species, except the first two, were Inadequate in many respects, so that accurate identification was difficult. Lee's (1937) revision went some way towards clarifying the situation, but he was hampered by having only a few specimens for examination. With an abundance of material of all the Victorian species, some collected in the field and some obtained by laboratory breeding, it has been possible to make a full analysis of their distinctive features and to prepare descriptions of the immature stages, which were previously unknown except in the case of !?. inconspicua. This paper also includes a description of a new species, T. victoriensis, n. sp., and information on the biology and distribution of the genus in Victoria. Biology. The Australian species of Theobaldia are bush mosquitoes. They are present in scrub along creeks, in the bush, and are especially numerous in upland forests, where the humidity is higher and the temperature lower than in the open country. Their inability to withstand high temperature and low humidity severely restricts their distribution. Thus, while they are widely distributed in south-eastern Victoria, in the north they are practically confined to hilly and mountainous country. T. inconspicua is more adaptable than the other species and is found at lower altitudes and in more exposed situations. The three species, T. hilli, T. frenchi and T. victoriensis, are man-biting mosquitoes and become very troublesome in late summer and autumn. During the day they fly close to the ground and confine their attacks mainly to the legs. ' After sunset they rise higher, biting the arms but almost never the face. T. inconspicua and T. Uttleri do not attack man. This difference in feeding habits tends to give a false impression of the relative abundance of the various species. Adults of T. inconspicua are not common in the field, but judging from larval numbers, it is by far the most abundant form. The larvae are very numerous in rock and ground pools shaded by trees or grass.