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XVIII. On the Genera of the Cossonid^e. 
By T. Vernon Wollaston, M.A., F.L.S. 
[Read 2nd June, 1873.] 
Having determined during the past winter to examine 
critically the structural characters of the various genera 
of the CossonidcB (so far as accessible) which have hitherto 
been published, I soon perceived that a very small pro- 
portion of the numerous species which were submitted to 
me could by any possibility be embraced by the 29 groups 
which were acknowledged by Lacordaire, and which have 
been admitted subsequently (with two or threS additions) 
into the Munich catalogue. And moreover the excessive 
inaccuracy of the greater number of the diagnoses, as 
given by Lacordaire- ( — for which however he was not 
himself responsible, they having simply been epitomized, 
at times perhaps somewhat in haste, from the different 
authors by whom they were originally compiled), made it 
but too evident that, in order to define them aright, no 
asserted peculiarity could be trusted as necessarily true, 
but that every single feature would have to be collated 
afresh, and on an independent basis. This being the case, 
it will at once be seen that my object in the present memoir 
has not been to monograph the species ; and therefore in 
two or three extensive and Avell-established genera, such as 
Cossonus and Rhyncolus, I have been content to select a 
few types, from distant parts of the world, and to treat 
them as representing their respective groups. Yet this 
very method of proceeding has involved the necessity of 
examining at any rate certain species with the utmost 
care ; and as an accurate list of these will be found at the 
close of my paper, it follows that the members of the 
family which are there catalogued (amounting to 253) 
may be looked upon as arranged systematically in accord- 
ance with my own viexos. 
At the same time I would not intend to imply that no 
other representatives of the groups which are more par- 
TRANS. ENT. SOC. 1873. — PART IV. (OCT.) I I 
