360 REVIEWS AND BOOK NOTICES. 
higher the elevation or the colder the climate, the rougher and more 
. 
scarcely any traces of striæ; var. obscura, elytra distinctly sulcate, 
but not deeply, is from Colorado and Southern Idaho. As we 
advance to the west the elytra are more deeply sulcate, as in 
var. arata, while var. sulcipennis, from nearer the Pacific coast, 
has deeply sulcate elytra, with very convex interspaces. The same 
variation of sculpture occurs in Calosoma luxatum Say, which 
starts in Colorado with comparatively smooth elytra, until in Van- 
couver we find the elytra covered with lines of granular elevations, 
forming the variety knowii as C. pimelivides Walker. The two ex- 
tremes of each series above noted appear to differ widely from 
each other, and to be entitled to rank as distinct species. In the 
foregoing remarks reference only has been made to variations 
within specific limits. ‘The same law appears to hold between dif- 
ferent species. In the genus Omus the most roughly sculptured 
species occurs in Washington Territory (O. Dejeanii Reiche), and 
the smoothest (O. levis Horn) from near Visalia, California. The 
ject of the preceding remarks is to explain what appears to be a 
law of variation for our western slope, and thus cause the unnec- 
essary multiplication of species, founded on slight characters, to 
be avoided. 
Species everywhere in our fauna appear to be distributed on 
lines of country presenting as nearly as ible similar meteoro- 
logical conditions. ‘Thus many Oregon forms extend southward 
into California, gradually seeking ‘a higher mountain habitat as the 
region becomes warmer. Two species illustrate this — Tragosoma 
Harrisii and Phryqanophilus collaris. Both extend their habitat 
from Maine to California, following the cooler regions westwar¢ 
from Maine through the Canadas and Red River region, thence 
northward nearly to Sitka. From the latter point southward to 
Oregon both occur at the ordinary level, and rising as a mo 
ion is reached, until at the latitude of Visalia they 
occur only a short distance below the snow-line, at an altitude of 
from ten to twelve thousand feet. 
From Southern California species have extended along the des- 
ert regions bordering the Colorado river to Utah. Two instances 
are presented in the collection just examined—Culosoma semileve 
and Anisodactylus piceus. Species advancing from the region just 
cited cannot be expected to cross the Rocky Mountains. Our 
common Harpalus caliginosus extends westward over all obstacles 
until the base of the Sierra Nevada is reached. It has not yet 
octurred in California proper.” 
__ The volume concludes with important papers on the Hemiptera 
by Mr. Uhler, and an extended essay on the Orthoptera by Prof. 
. _ 'Fhomas, illustrated by two plates. 
