OF WASHINGTON. 385 



One specimen was obtained near Salt Lake on June 13. This 

 is a common species in various sections of the United States west 

 of the Mississippi river. Dr. Blaisdell sent several specimens to 

 me which were captured in fresh water near San Diego, Cal. It is 

 found also near San Francisco, and in various parts of California, 

 as also in Nevada, Washington Territory, and Oregon. 



It differs from C. inter rupta Say in the shape of the palae and 

 in the absence of rastration on the pronotum, etc. 



Dr. Marx read the following communication : 



ON SPIDERS' WEB. 

 By DR. GEO. MARX. 



About a year ago I received from the Botanical Division of the 

 Department of Agriculture a sample of a very curious, white, 

 flossy, silk-like substance which had been found at Vallecita, Cal 

 ifornia. The postmaster who sent it wrote as follows : 



u Accompanying this is a small memorandum-book, between 

 the leaves of which you will find a strange (to me and others) 

 substance, of which I should like to know the nature whether it 

 is vegetable, animal, or purely aerial. For the last five years, in 

 the months of October and November (after the first shower of 

 rain), I have observed this material come floating in the air (in 

 currents of air moving from the west) , and frequently and con 

 tinuously for days and weeks, alighting in the roads and fields. 

 I am situated about one hundred miles from the Pacific coast and 

 about 2,000 feet above the level of the sea. In the middle of the 

 day the western currents of air or wind are quite brisk, and I do 

 not meet this thing then, but when it is calm I have caught this 

 floating, fleecy substance in my hand, and in the morning in going 

 along the public road I could see it lying about on the rocks and 

 dirt quite plentiful ; it adheres to everything it touches ; thus in 

 some of the samples I send you there will be found other foreign 

 matter that the fleecy web brought along when gathered. I 

 could not gather it with my fingers no, I do not mean that 

 after I had gathered it with my fingers I could not lay it down 

 again, because of its propensity to cling to everything touching it 

 This that I send was found clinging to weeds and stubble in the 

 field where grain had been harvested. I gathered it in crossing 

 a small field once (about fifty perches) . Some of its fibres were 

 stretched out from one weed or grass to another, as much as three 

 and one-half feet." 



The substance from California was of such a peculiar nature 

 that it was difficult to decide upon its true character without sub 

 mitting it to a thorough chemical test. 



