SCIENCE-GOSSIP. 



117 



only one-seventh were European ; and the com- 

 paratively limited but characteristic group of the 

 Midasidae, of which only three out of eighty-eight 

 species were indigenous to this continent. 



Now let us see what progress has been made in 

 directions where a competent dipterologist has 

 made a special study of some particular group and 

 brought it up to date, in every case with valuable 

 additions to the lists of species. In Schiner's pre- 

 viously mentioned Catalogue of European Diptera 

 (1864) the genus Sciara comprised 81 species, but 

 Winnertz, in an admirable monograph of all the 

 European species, brought the total up (in 1868) 

 to 147, to which must be added about 70 more 

 described since that date. In his paper, published 

 in 1893, Eaton added to the 12 European species 

 of Psychodidae already known no less than 24 

 new ones, being from England alone. Chilosia, an 

 extensive genus of Syrphidae, was represented in 

 1864 by 93 European species, a total which Becker, 

 in his excellent monograph on the genus (in 1894), 

 augmented by no less than 63, the genus now 

 being considered to be represented by about 170 

 European species. On the other hand, hosts of 

 species created by Robineau Desvoidy on minute 

 and unstable characters, and scores of others 

 " described " by Walker, have been sunk or placed 

 aside as unrecognizable. The instances just quoted 

 are certainly rather exceptional, but they go to 

 prove that in many directions our knowledge of the 

 order is very far from complete. 



Reverting to the subject of the possible number 

 of existing species, it may be taken that there are 

 at least as many specific forms in a given area 

 abroad as there are in a European area of corre- 

 sponding size; so that, as Europe (with 11,500 

 species) forms only the one-seventeenth part of the 

 temperate and tropical land surface of the globe, 

 we can reasonably expect the Diptera of the whole 

 world to be represented, on the same proportionate 

 scale of species to area, by 195,500 species, to 

 which must be added some thousands extra on 

 account of the phenomenal abundance of insect 

 life in the tropics. This estimate brings us pecu- 

 liarly close to that of Schiner, made thirty years 

 ago. The interior of Brazil, almost the whole of 

 India, China, Japan, Central Africa, Madagascar, 

 Borneo, Celebes, Papua, Ceylon, and certain other 

 countries and large islands must be simply teeming 

 with thousands of species new to science. 



It will thus be apparent that even beginners 

 have very reasonable chances to discover species 

 new to Britain or even new to science, especially if 

 collecting in Scotland, Ireland or Wales ; whilst 

 on the Continent the best part of Russia is still 

 quite virgin ground, and Spain, Portugal, Turkey, 

 Roumania, Servia, and other parts have as yet by 

 no means furnished their proportionate quota of 

 peculiar forms. 



The initial drawbacks to the British student is 

 the lack of available literary assistance. Walker's 

 " British Diptera," though written in English, is 

 obsolete, difficult to obtain, and expensive. Con- 

 tinental works are written in French, German, 

 Latin and Italian, whilst of late years some useful 

 papers have been published in Dutch and Russian, 

 notably Van der Wulp's excellent work in Dutch, 

 with splendid plates, the "Diptera Neerlandica " 

 (unfinished). All this tends to discourage British 

 enthusiasts, who as a rule are not linguists to the 

 extent necessary to study these books. Moreover, 

 they are generally more or less youthful. Though 

 the pursuit of entomology, if commenced early in 

 life, is frequently kept up indefinitely, it is seldom 

 taken up to any real advantage by middle-aged 

 persons, and it is with this conviction that I 

 address my remarks principally to the younger 

 collectors. A further source of embarrassment is 

 the non-existence of reference collections. True, 

 there is the British Museum collection, but for 

 collectors out of London, who are in the great 

 majority, it can be of but little assistance. 

 Naturally the first thing one wants to do after 

 collecting is to name one's captures, otherwise the 

 incentive to continue is lost. 



Such assistance as I can render to any one 

 taking up the study of the Diptera, by advice or 

 naming their captures, I shall be very pleased to 

 give, provided the specimens are in good condition, 

 and under no circumstances carded. I recommend 

 long Carlsbad pins, the flies to be placed about 

 one-third down the pin from the head, and unset, 

 so that they may be exchangeable with Continental 

 and foreign correspondents. In every case a label 

 should be attached, giving date and locality. At 

 any season of the year a commencement may be 

 made ; for, excepting during winter frosts, some 

 Diptera are to be found, if properly looked for. 



Diptera are abundant in individuals and numerous 

 in species, and occur in every kind of locality. 

 They can be caught with the ordinary butterfly- 

 net, and in hundreds by sweeping the grass and 

 herbage. The two-winged flies will, by their 

 infinite variety, develop an interest for them in 

 any one who cares to make the experiment of 

 taking up their study. 



352, Strand, London, W.C. 



New List of Australian Birds. — The Trustees 

 of the Australian Museum at Sydney have recently 

 issued, in one volume, the first and second parts of 

 a new edition of the "Catalogue of Australian' 

 Birds." It comprises the orders Accipites (diurnal) 

 and Striges (nocturnal birds of prey). A useful 

 and complete list of references and synonyms is 

 given under each species, with full descriptions of 

 both sexes of adult birds, and frequently also of 

 the immature stages. It refers more especially to 

 those species in the Sydney Museum, but will be 

 useful as far as it goes. 



