necessity for such a work is proved by the encouragements which we have already received from Entomologists in all parts of the world, upon the first announcement of our schema.
Large gaps in our knowledge will be seen to exist still in many orders of Insects, notably among the generic classification of the Hymenoptera and Diptera. The number of described species of Insects of all order is largely increasing every day.
We are assured that many well-known specialists will agree to lend us their aid, in order that our Genera Insectorum may take a high rank among Entomological publications.
. P. WYTSMAN.
Brussels (Belgium), 108, Boulevard du Nord.
FORM AND TERMS OF PUBLICATION
It is proposed to issue the Genera Insectorum in quarto parts, each containing about 72 pages of text, and 7 plain or coloured plates, as the needful illustrations may require.
The price of each part is fixed at One Pound sterling.
The work will be complete in about 7 5 parts.
PLAN OF THE WORK
1 . General characters of each family. — 2. Synonymy of the genus. — 3 . Description of each genus. — 4. Geographical distribution of the species. — 5 . Number of each species known in Europa, America, etc. — 6. Additional notes on anatominal details, etc., if required.
We hope that those who receive this circular will endeavour to induce the University Libraries and other Public Libraries in their neighburhoad to take copies.
FIRST LIST OF CONTRIBUTORS
Coleoptera : Messrs. M. Belon (Lyon); E. Brenske (Potsdam); J. Bourgeois (Markirch); H. Boileau (Paris); C. Felsche (Leipzig); E. Fleutiaux (Paris); A.Grouvelle (Paris); W. Horn (Berlin); M. Jacoby (Londres); K. Jordan (Tring); Ch. Kerre- mans (Bruxelles); P. Lesne(Paris); A. Leveille (Paris); F. Ohaus (Hambourg); E. Olivier (Moulins); M. Pic (Digoin); A. Raffray