130 Notices of Books, [January, 
The following is an interesting contribution to our as yet very 
scanty knowledge of what may be called the local physiognomy 
of the faunas of different countries : — “ In all the species enu- 
merated in the following list- — 25 in number — the Colorado 
examples (when the species have been found to occur there) and 
the Pacific Coast individuals are larger, and in some cases with 
longer and more pointed wings, than in those from Labrador and 
the Eastern Atlantic States, and in a few instances show a ten- 
dency to become lighter in colour.” 
The following passage is also worthy of special attention : — 
“ It will be seen from the facts we have presented that the 
moths probably follow, as regards size, a law the reverse of that 
established by Prof. Baird for the birds and mammals, who 
shows that they decrease in size southwards, though his law of 
increase in the length of certain peripheral parts westward also 
obtains in the Lepidoptera. The increase in size westwards is 
of course equivalent to the well-known southward increase of 
size in insects, though in a few species of inserts the Coloradan 
and Californian specimens are larger than Floridian and Texan 
insects of the same species. Of the insects mentioned in the 
list Plusia Hockenwarthi is the clearest example (1) of the law 
of increase in size westwards and southwards ; (2) increase in 
length of peripheral parts ; (3) brighter^ deeper colours west- 
ward.” 
Dr. Packard is decidedly opposed to the theory of Heer, of an 
“ inter-continental bridge between the temperate zones of Ame- 
rica and Europe, and of America and Asia.” 
The work is admirably and abundantly illustrated : twelve 
large plates, with many hundred figures, represent not merely 
the moths as described, but the characteristic venation of their 
wings, and other important morphological details. Upon Dr. 
Packard the work reflects the highest credit. He has, evidently 
with a most lavish expenditure of time and labour, produced a 
most valuable contribution to zoological science, in which accu- 
racy of detail and a large and philosophic spirit are equally con- 
spicuous. Nor, whilst expressing our appreciation of the author, 
must we forget to commemorate the far-sighted and enlightened 
policy of the American Government in promoting such researches, 
and the more than royal munificence with which this and similar 
volumes are presented to learned societies, public libraries, and 
the conductors of scientific journals throughout the civilised 
world. Were this example followed by governments which have 
even greater opportunities, an absolutely priceless selection of 
materials would be placed within the reach of scientific men, 
and the verification of theories would be rendered a compara- 
tively easy task. 
