February 14, 1908] 



SCIENCE 



271 



sian Eiver. Should a part of the upper course 

 of a tributary have been transferred from one 

 system to the other, it would have carried with 

 it only such forms as it harbored, thus intro- 

 ducing to the recipient basin a comparatively 

 limited fauna. This condition is apparently 

 what we find in the Russian River system. 

 Its fauna is like that of the upper courses of 

 the streams tributary to the Sacramento which 

 flow from the western side of the great valley, 

 the channel forms common to the main river 

 being absent. 



It is fair to conclude that the fish fauna of 

 the Russian River was probably derived from 

 the Sacramento system, and a study of the 

 species offers the suggestion that the inter- 

 mingling of their waters, by which the species 

 were introduced, was not afliected by a main- 

 channel connection, but rather by a process of 

 stream-robbing something like that described 

 by Holway, only that the transfer was in the 

 opposite direction. J. 0. Snyder 



THE MOTH-PROOFING OF WOOLENS 



When living in Swatow, China, my house, 

 like all dwellings within the tropics, was in- 

 fested with various kinds of insects. In ex- 

 perimenting with diverse substances with a 

 view to self-protection against insect pests, I 

 found that alum was a perfect preventive of 

 the ravages of moths among woolens. 



It is well known that the female clothes- 

 moth deposits her eggs in woolen goods, and 

 that the worm-like larv£e hatched from these 

 eggs subsist upon the wool until they attain 

 the general form of the adult moth. The 

 Chinese, who are the great practical econo- 

 mists of the world, do not ordinarily wear 

 woolen garments. They are well protected 

 from cold by an interlayer of raw cotton be- 

 tween the lining and the surface fabric of 

 their winter apparel, which is often made 

 from very light-weight silk or linen. Never- 

 theless, the clothes-moth is ubiquitous in 

 China, and undisturbed woolens are soon rid- 

 dled by its developing progeny. 



I gave the alum a severe test by immersing 

 picture-cords made wholly of wool, in a satu- 

 rated solution for several hours, and after- 



ward using the cords to suspend framed pic- 

 tures. These cords, numbering a score or 

 more, sustained heavy pictures for over three 

 years, without showing sign of weakness. 



A basket of soft worsteds, that I had 

 used in testing the Chinese for color-blindness 

 by the Seebeck and Holmgren method, were 

 likewise treated with alum, and left uncovered 

 and undisturbed for more than a year without 

 attack from moths. The colors of these wor- 

 steds, although diverse and delicate, were not 

 altered by the soaking in alum water. 



Woolen shawls and other articles were forti- 

 fied against moths in the same way, and re- 

 mained intact for several years. 



The alum does not evaporate, and is there- 

 fore permanently efi^ective in unwashed fabrics. 



There is apparently no reason why wools 

 used in manufacturing cloth, rugs and carpets 

 should not be so treated with alum as to be- 

 come moth-proof. Crude alum is inexpensive 

 and probably one pound of it in four quarts 

 of water would make a solution of suflicient 

 strength for the practical result aimed at. 

 The commercial value of woolen goods would 

 be enhanced by this process, and " the house 

 beautiful " would be more easily kept. 



Holland, writing of these troublesome im- 

 migrants from the old world, says (" Moths," 

 p. 426) that the depredations of clothes-moths 

 cost the citizens of the United States annually 

 a sum of money which is enough in amount 

 at the present time to pay the interest on the 

 national debt. Adele M. Fielde 



Seattle, Wash., 

 November 22, 1907 



pink katydids. 

 To THE Editor of Science: Referring to 

 your page 639 (Vol. XXVI.), I have captured 

 pink katydids at East Hampton, L. I., prob- 

 ably on four to six different occasions in the 

 last twenty years. One year — ^I should say in 

 the seventies — I had three at one time. No 

 one there had ever seen any — although no pro- 

 fessional entomologist was in town. I also 

 found one at South Lyme, Conn., in the sum- 

 mer of 1906. All that I have ever found 

 were a bright shell pink. I did not note the 

 sex of any of my specimens, which were all 



