92 
REVIEWS. 
of the species. In relation to any of these, he may expand his work, by 
beginning afresh from the foundation. But, in every case, he commits a 
fault by so doing. If such a preliminary labour is necessary, the interests 
of science in general, and, ultimately, the purposes of the Fauna, would be 
better served by making that the subject of a distinct work ; which should 
take quite a different form, and aim at other ends than this is restricted to. 
But, apart from what the writer may be tempted to do of this kind, he 
may, without impropriety, extend his work, in other ways, beyond the 
strictly necessary objects aforesaid. Such legitimate additions would be— 
to give a comparison of the particular Fauna with that of the neighbour¬ 
ing countries; the geographical range of the species, as far as this is 
known ; the first discoverers of species within the local limits, and the ear¬ 
liest or most successful observers of the transformation, natural economy, 
and the like. Everything, besides, that the author can do to direct the 
mere collector, for whose especial use he writes, to the sources of more 
complete information, and to smooth the way for him to a more compre¬ 
hensive and profounder study of the science, may be thankfully accepted, 
provided he takes care always to keep in view the more direct design of a 
Fauna, and does not make it too voluminous. If so much be not obliga¬ 
tory upon him, at least he incurs unqualified blame if the form or matter 
of his work be such, as not only to leave the student at fault, but even to 
put impediments in his way. 
Of all the essays in the nature of a Fauna of this order, we consider the 
lists of Austrian Diptera, by Dr. Schiner, in the Transactions of the Zoolo¬ 
gical and Botanical Association of Vienna, to be the most judicious, cha¬ 
racterized as they are by accuracy in the determination of the species. A 
more distinct indication of the best descriptions and figures, the omission 
of many redundant synomyms, a more methodical way of exhibiting the 
local range, and, as far as space may admit, the addition of the chief spe¬ 
cific characters, and of the essential differences from the nearest allied 
species, is all that seems wanting in them to satisfy every necessary re¬ 
quisite of a Fauna, without enlarging it to excess by the introduction of 
extraneous matter. When Mr. Walker’s work is tried by the same rule, 
it appears to fall very short of what a Fauna of Britain ought to contain. 
The species already known as British are not fully enumerated (in the se¬ 
cond volume especially) ; neither are the species given all unquestionably 
indigenous ; on the contrary, many are introduced on mere conjecture and 
probability—as a considerable proportion of the species of Ceratopogon and 
Cecidomyia in the third volume. In the second volume many are men- 
