March 17, 1899.] 



SCIENCE. 



417 



studying the fishes of the State of New York, 

 to examine numerous specimens of the Common 

 Whitefish from the Great Lakes and interior 

 lakes of New York and of the so-called Labra- 

 dor Whitefish from lakes of New York and New 

 Hampshire and from rivers in New Brunswick 

 and Labrador. As a result of these investiga- 

 tions he is forced to the conclusion that Rich- 

 ardson's species, Coregonus labradoricus, is 

 Identical with the Common Whitefish, Core- 

 gonus clupeiformis, there being no characters 

 by which the two can be distinguished. Every 

 individual of the Common Whitefish, young 

 and old, was found to have teeth on the tongue 

 and to possess the other characters bj' which 

 Richardson's species has hitherto been sep- 

 arated. 



This conclusion has an important bearing 

 upon fish cultural operations by the States and 

 the United States, as it will tend to simplify 

 the work of artificial propagation and, perhaps, 

 extend its scope. 



Taeleton H. Bean. 



Washington, D. C, March 3, 1899. 



A DATE-PALM SCALE INSECT. 



Db. a. S. Packard writes from Biskra, Al- 

 geria, January 23, 1899 : "I find myself in this 

 oasis of the northern edge of the Sahara, where 

 there are 170,000 date palms. In a beautiful 

 garden I found a date palm, indeed several, af- 

 fected by Coccids, which I enclose." The Coc- 

 cids are crowded on the pieces of leaf and prove 

 to be Aonidia blanchardi, Targioni-Tozzetti, 

 Mem. Soc. Zool. France, ,1892, Vol. V., p. 69. 

 The insect, however, is not an Aonidia, but be- 

 longs to Parlatoria, and must be called Parlatoria 

 blanchardi. It was originally found in the oasis 

 of Ourir, and has never, I believe, been noticed 

 since its original description until now redis- 

 covered by Dr. Packard.* The figures of Tar- 

 gioni-Tozzetti represent it well, except that in 

 one of them (Fig. 3) there is an impossible lobule 

 between the median interlobular squames. The 

 female turns bright olive green on being boiled 

 in caustic soda. There are four small groups of 

 circumgenital glands. This insect is likely to 



"^Unless Haskell's P. proteus var. Palmiv, found in 

 Australia on date palms imported from Algeria, is the 

 same, as indeed seems likely. 



be of some economic importance, as it is allied 

 to, though easily distinguished from, Parlatoria 

 victrix, Ckll. ; which, introduced from Egypt, 

 has proved a pest on date palms in Arizona, 

 California and Queensland. The manner of 

 the infestation is quite the same in the two 

 species. 



T. D. A. COCKEEELL. 



Mesilla Park, N. M., February 16, 1899. 



THE CHOICE OF ELEMENTS. 



To THE Editor of Science": Once upon a 

 time, according, I believe, to Messrs. Gilbert 

 and Sullivan, a magnet hanging in a shop win- 

 dow fell in love with a silver churn, but, to its 

 great distress, was unable to awaken any re- 

 sponse. Its pathetic plaint ran : 



" If I can wheedle 

 A nail or aneedle 

 Why not a silver churn." 



I used to think the magnet very unreasonable, 

 because I supposed the atoms of iron and steel 

 were necessarily drawn to it willy nilly, while 

 there was no such tendency in the silver atoms, 

 which were consequently quite unable to re- 

 spond to its call. Major Powell (Science, Feb- 

 ruary 17th) puts the matter in a new light, 

 which awakens my sympathy for the magnet. It 

 appears that the particles have choice. Both 

 common sense and the dictionary tell us that 

 choice is the power of choosing. Thus it 

 was not of necessity, but of their free will, 

 that the nails and needles were so responsive. 

 The silver churn evidently considered the mag- 

 net ineligible. The case of the latter is a truly 

 sad one, worthy of all serious commiseration, 

 for if, as Major Powell tells us, the particles 

 have intelligence, why should they not have 

 love also '? True, the magnet as a whole does 

 not know, but what can assuage the grief of 

 each of its myriad particles? Is there any hope 

 that in time the silver will think better of it? 



T. D. 

 Harvard Medical School, February 27th. 



ASTRONOMICAL NOTES. 

 tuttle's comet. 

 This comet was discovered by Mechain at 

 Paris in 1790. Only a few observations were 



