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alone that he has had practical experience. The earliest which 
we need to consider is that of Walsingham and Durrant.^® This 
code formulates the method of fixing the types of genera which 
was in common use until the present century, and appears still 
to be favored by some European scientists. The most important 
principle involved is its acceptance of restrictions. In all codes 
the first provision is that the type shall be selected from among 
the species originally included in the genus, and this is the only 
restriction now generally accepted as affecting the fixation of the 
type. The rules formulated by Walsingham and Durrant, how- 
ever, express the principle so widely followed in the past, provid- 
ing that if any writer used the genus subsequent to its descrip- 
tion, and eliminated part of the originally included species, the 
type must be selected from those of the originally included species 
which he retained in the genus. In some cases this may be very 
reasonably applied, but it is weak, and hence scarcely to be con- 
sidered as a generally applicable rule for the following reasons: 
First, in the early days of entomology, works covering the en- 
tire animal kingdom, y.et of some scientific pretension, were often 
published. Obviously such works could not attempt to mention 
every known species unless they were purely systematic, hence 
only a few, or even one, was mentioned as an example of each 
genus. No intention of the writer to restrict the genera by such 
means can reasonably be assumed, yet such a citation of a single 
species in illustration of a genus has been taken as a valid fix- 
ation of the type. A good example is the genus Hesperia Fab. 
This genus originally included all of the Lycaenidae and Hes- 
periidae. Cuvier mentioned it, citing malvae Linn, alone as an 
example.-'^ It is argued by some writers that this action fixes the 
type, but it is quite clear that the inclusion of this particular 
species was incidental. Thirty-nine years later another work of 
Cuvier made the same citation, with a footnote which indicates 
that his use of Hesperia was intended to be identical with that of 
Fabricius."^ A second weakness with these restrictions is that 
they may be due to the fact that the restricting work dealt with 
only a limited fauna, or a certain collection, as in the case of 
Lord Walsingham and J. Hartley Durrant, Rules for the Regulation of 
Nomenclature, London, 1896. 
The International Rules provide also for the designation of types of 
genera originally described without included species. 
^ Cuvier, Tabl. Elem. 592, 1798. Fide Scudder. 
Cuvier, Animal Kingdom iv, 285, 1837. 
