Dr. Horn's Notes on the habits of Californian CoJeoptcra. 289 



NOTES ON THE HABITS OF A FEW CALIFORNIA COLEOPTERA. 



BY GEO. II. HORN., M. D. 



AMPHIZOA IXSOLENS Lee. 



The knowledge of the habits of this insect has long been a desidera- 

 tum to science. The locality from which it was obtained was not even 

 known. The specimens from which the original description was made 

 was obtained by Dr. LeConte from Mr. Rath von, of Lancaster, Pa., 

 from whom no information could be obtained, except that they came 

 from California. The first specimen sent me was from Fort Klamath, 

 Oregon, immature and in a damaged condition. Shortly after receiv- 

 ing this, I went to North-eastern California, near the head waters of 

 Pit river — a tributary of the upper Sacramento. Near Fort Crook I 

 saw the first living specimens, though so rare and difficult to be ob- 

 tained, that I was satisfied with the securing of a few specimens, with- 

 out risking the loss of any in the observation of their habits. From 

 Fort Crook I went to Surprise Valley, on the boundary line between 

 California and Nevada. Here I found them very abundant, as well 

 as on the western slope of the Sierras, in the creeks forming the three 

 head branches of Pit River. 



Amphizoa is as essentially sub-aquatic in its habits as any of the Par- 

 nidoe, which it closely resembles in its terrestrial aud sub-aquatic mo- 

 tions. They occur more abundantly in stony creeks, and preferably 

 on stones of which some portion projects from the water. This enables 

 them to come to the surface for fresh air without detaching themselves. 

 They live in herds, so to speak. I have found eight or ten crowded 

 closely together, adhering to one small stone. Living in swift currents, 

 they naturally adhere to rough stones. I have found many, however, 

 adhering to the under side of grass sods which project from the shore 

 into the stream. 



"When placed on land, they run with moderate rapidity, though 

 rather clumsily. They are very poor swimmers, being scarcely able to 

 make any progress, even when thrown upon still water. The light- 

 ness of their bodies keeps them from sinking, and they can only take 

 position under water by lodging against a stone or root, and walking 

 under. When under water, they move with much greater ease than 

 on land, the peculiar shape of their bodies affording but little resistance 

 even to strong currents. 



PROCEEDINGS EXT. SOC. I'lIILAD. JANUARY, 1867. 



