PRESIDENTIAL ADDRESS. AUSTRALIAN TREE FROGS OP THE GENUS HYLA. By Stephen J. Copland. [Delivered 27th March, 1957.] Synopsis. All 44 known continental species and subspecies of the genus Hyla are dealt with in a purely systematic way, but an attempt has been made to indicate at least interesting and important notes on ecology, colour in life, breeding-habits and other matters not directly bearing on the present approach. A standard description of each frog is given to facilitate comparison. It was thought essential to include original descriptions to serve as courts of appeal, especially as so many type specimens are vmavailable overseas. Variation in nearly 3000 frogs has been studied, and contributions of other authors have been discussed. Fairly comprehensive lists of locality records are included as a basis for the more accurate study of geographical distribution. Short diagnoses have been added to the key to simplify identification. Bight new specific and subspecific names have been given. Introduction. The purpose of this paper is to provide a basis for work on the Australian tree frogs or Hylids. It was felt that this would be best served by providing a complete set of standard descriptions of all species so that comparison of species can be made conveniently and directly character by character. It has been thought essential to include all original descriptions. They must serve as the final checks because the ultimate court of appeal to type specimens cannot be made in Australia. Most types are overseas and it would be impossible in any case to trace many of them. To the standard and original descriptions have been added notes on variation based on the individual examination of nearly 3000 frogs from the collections of most museums in Australia and a fairly large number of specimens in the author's collection. Geographical distribution has been dealt with by lists. Finally, problems associated with each species and the contributions of other authors have been discussed. A short diagnosis of each species has been added to the key to facilitate identification. One reason for this work is that the Australian Hylidae lack any comprehensive paper dealing with them as a unit. All other Australian frogs have been monographed: the Ranidae by Boulenger (1920), and the Microhylidae and Leptodactylidae by Parker (1934, 1940). Keferstein (18686) dealt with all species known at his time in the only work on Australian frogs to be published yet, but his descriptions are often short and other aspects are hardly mentioned. Also some frogs have the barest treatment. Boulenger in his great catalogue dealt with the frogs of the whole world (1882), and besides a standardized description was able to give only a short synonymy and the localities of but few specimens. Nieden (1923) in the main gave only a redescription from Boulenger, adding occasional points and including species new since that author. Loveridge (1935), who made an essential contribution to this study, listed all Hylidae known at the time, gave many locality records, and did much towards clearing up problems, notably those of the lesueurii and etoingii groups. It has been impossible to deal fully with even the more important references by the many authors who have discussed Australian Hylids, yet an attempt has been made to indicate briefly interesting and important notes on ecology, colour, breeding habits and other matters not directly bearing on the present systematic approach to all the continental species known. It is expected that some of these fields will be treated at length in forthcoming publications by Moore and Colefax. This study of variation and distribution has strongly suggested certain patterns of migration from the north. The picture is of at least three phases — one comparatively remote Proceedings of the Linnean Society of New South Wales, 1957, Vol. Ixxxii, Part 1.