Februabt 24, 1911] 



SCIENCE 



307 



nai'j' teDiperature, causes its decomposition 

 into " triphenylmethyl," (CsHJ^C. 



An investigation of the ethanes containing 

 a smaller number of phenyl groups, from one 

 up to five, would obviously be calculated to 

 throw light on these points. This work has 

 been carried out and it has been found that 

 a very stable compound, which was formerly 

 regarded as being hexaphenylethane, actually 

 possesses a different constitution. It has also 

 been shown that, in certain respects, there is 

 a decrease in stability and an increase in 

 chemical reactivity as the number of phenyl 

 groups in the ethane molecule becomes 

 greater. Thus, for example, pentaphenyl- 

 ethane, (CJIJ^C-CHCC.H,), is decidedly less 

 stable than tetraphenylethane, (C„H5),CHCH- 

 (C,H,), 



The final link in the chain of proof has been 

 furnished by Schlenk, who has just shown that 

 if the pentaphenylethane be heated with a 

 neutral solvent of high boiling point, it is 

 decomposed into triphenylmethyl and tetra- 

 phenylethane, in the manner indicated by the 

 dotted line in the formula, 



(C„H.)3C CHlCaH,),; 

 the tetraphenylethane results, of course, from 

 the combination of two of the groups, 

 CI-I(C,H„)„. It follows, therefore, that there 

 is no difference, in principle, between the be- 

 havior of pentaphenylethane and hexaphenyl- 

 ethane towards solvents; when in solution, 

 both give triphenylmethyl, the latter at the 

 ordinary temperature, the former only when it 

 is heated. 



In view of these results there is no ground 

 for doubting that the colorless solid obtained 

 by Gomberg is really hexaphenylethane, 

 (C„H5)3C-C(C„IIJ3, and that its passage into 

 solution, at the ordinary temperature, suffices 

 to resolve it into two molecules of colored tri- 

 phenylmethyl, (C„H,)3C. 



J. Bishop Tingle 

 McMasteb Universitt, 

 Toronto. Canada 



SPECIAL ARTICLES 

 SUGGESTIONS AS TO THE CULTURE OF BUTTERFLIES 



Butterflies, with their clear-cut color pat- 

 terns and brilliant hues, their remarkable 



polymorphism seen in the occurrence within a 

 single species of two or more seasonal forms, 

 or of melanic, albinic or other varieties often 

 limited to individuals of one sex, furnish a 

 most inviting field for the student of evolution 

 and heredity. The fact that in America, at 

 least, no precise and long-continued work on 

 heredity in diurnal lepidoptera has been under- 

 taken hitherto is probably due in part to the 

 belief that the mating of butterflies, occurring 

 usually in the air, would be difiicult to bring 

 about in small cages; though the mating of 

 moths under such conditions is generally 

 known to be an easy matter. It is my purpose 

 in this article to correct this false impression 

 in regard to the mating of butterflies, and to 

 make other suggestions as to methods of car- 

 ing for this dainty live stock, of -marking indi- 

 viduals to indicate their pedigree, and of 

 preserving them in a more compact, per- 

 manent, convenient fashion than the usual im- 

 palement on long pins in bulky drawers or 

 boxes. 



One who undertakes the study of the 

 heredity of butterflies may of course begin 

 either with live wild females, presumably 

 already impregnated, or with eggs already laid, 

 with larvae, or with chrysalids. For transpor- 

 tation over long distances chrysalids, or eggs 

 upon the food plant, are usually to be pre- 

 fered. Living plants with roots intact and 

 leaves covered with eggs may be shipped in 

 tin boxes by mail. But often only the imago 

 can be obtained. In this case, and always, if 

 the distance is not too great, sending live 

 butterflies by mail in Strong, cylindrical tin 

 boxes lined with moist blotting paper that is 

 held firmly in position is to be reco m mended. 

 I have found that Colias philodice, shipped 150 

 miles in this way, and shut up closely for 

 eighteen hours, stands the journey well, and 

 lays abundantly, if well fed with sweetened 

 water upon arrival. 



For purposes of identification it is of course 

 necessary for the student of heredity to label 

 each living adult butterfly. This is readily 

 done by writing the sign of the family and 

 individual with pen and ink upon the under 



