1929] 
Habits of Amphizoa 
383 
NOTES ON THE HABITS OF AMPHIZOA 
By P. J. Darlington, Jr. 
Amphizoa is such a curious beetle and is still so rare in 
collections that it was among my chief desiderata on a trip 
to the Northwest during the summer of 1927, when I was 
collecting “on shares” for Dr. J. G. Gehring. My introduc- 
tion to the insect was performed by Dr. E. C. Van Dyke, 
whom I chanced to meet on Mount Hood, and with this 
auspicious start a total of about 350 specimens, including 
all the American species of the genus, was secured in the 
various localities visited. Horn (Proc. Ent. Soc. Philadelphia 
6, 1867, p. 289) has compared the habits of these beetles 
to those of the Parnidse, but this proved so misleading in 
my case that I think some further notes on their collecting 
are justified. 
The three species have mutually similar habits. They 
occur chiefly in two sorts of places, either in gravel at water 
level along the banks of streams, or in masses of floating 
trash which have gathered against obstructions. In the first 
case they are nearly always at the side of an eddy or at a 
curve in the stream, or where for some reason the current is 
throwing up detritus. The collector soon learns to recognize 
likely spots by the presence of deposits of spruce needles or 
masses of foam. In favorable places the shores are often so 
undercut that the beetles must be sought in shallow caves or 
under overhanging rocks. Good collecting may be found in 
both swift and comparatively slow brooks, but in the latter 
the Amphizoa are usually in the rapid stretches. 
A few examples of the right sort of place are, perhaps, 
worth giving. On Mount Hood Dr. Van Dyke and I found 
Amphizoa insolens in trash which had been caught against 
bushes in a small brook, just where the latter crossed a 
sand-filled beaver dam. Numerous A. striata Van Dyke 
were collected in similar rafts of trash which had gathered 
