June, '05] ENTOMOLOGICAL NEWS. IQ7 



encouraged. With a poor describer at work a description may 

 be so indefinite as to give at most but an approximate idea of 

 the insect and its relations to its nearest allies. In such cases 

 the type becomes a " court of last resort " to which to refer, 

 and anyone who has attempted to solve Walker's descriptive 

 puzzles will appreciate the necessity of seeing the type speci- 

 mens on which these descriptions were based. 



But types are scattered in all portions of the globe and it is 

 frequently the case that the personal study is impossible. 

 Specimens may be sent for comparison with the type however, 

 and if the comparison be made by a good authority, the speci- 

 mens concerned should have an increased value over those not 

 thus compared. 



These and other facts have led to the establishment of vari- 

 ous grades of relation between the type and other specimens of 

 the species, and differing in their degree of importance. So 

 far as the writer can learn, this was first suggested by Mr. 

 Oldfield Thomas, F. Z. S., in a paper entitled "Suggestions 

 for the more definite use of the word ' Type ' and its com- 

 pounds, as denoting specimens of a greater or less degree of 

 Authenticity," published in the Procceedings of the Zoologi- 

 cal Society of London for 1893, P a & e 2 4 l > where the statement 

 is made that the term " co-type " had already been introduced 

 by Mr. C. O. Waterhouse. 



The ideas and definitions suggested in this paper were 

 later developed and somewhat modified by Lord Walsingham 

 and J. H. Durrant in a pamphlet " Rules for Regulating No- 

 menclature," etc., published November 2, 1896, by Longmans, 

 Green & Co. , this pamphlet being generally referred to as 

 the " Mertou Rules." 



This paper seems to have had a rather limited circulation ; 

 at least it is now almost impossible to obtain a copy of it, for 

 the writer knows of cases where standing orders for it have 

 been placed for several years in this country and in Europe 

 without result. It seems desirable, therefore, to place the 

 definitions of types as given in that paper before the Entomo- 

 logical public in some easily accessible place for reference. 

 These rules are as follows : 



