December 1S94.J 



PSYCHE. 



175 



poecilogonic forms, while preserving a 

 great resemblance in the adult state, 

 cannot be crossed and this inability to 

 cross facilitates the divergence of the 

 two species even if they come in 

 contact in some point of their habitat. 

 It is thus, that, according to Grote and 

 Smith, Agrotis haruspicaAwA A. riibi- 

 fera are the American representatives 

 of the European A. auger and A. riibi, 

 from which they difler only in the 

 genital armature of the male; but that 

 these modifications may be etlective 

 they should perhaps recede and deter- 

 mine the poecilogony instead of being 

 caused by it or produced by it. This 

 question is hard to solve at present and 

 stands with the numerous problems 

 that Romanes has stated in his work on 

 physiological selection. In other cir- 

 cumstances poecilogony seems to be 

 due to the varying nourishment of the 

 larvae. If certain caterpillars are 

 modified directly by the supporting 

 plant as is known to be the case among 

 a great number of species, we know 

 also that some are adapted definitely to 

 a determined plant and are protected 

 by a permanent form, a difterent livery. 

 Poulton has stated, as well as other 

 authors, that many caterpillars die of 

 hunger rather than touch nourishment 



for which their race has lost the habit. 

 Perhaps it is to poecilogony of nourish- 

 ment that we should attribute the 

 differences found in the caterpillars 

 of Cuciilia verbasci and C. scrofida- 

 riac, moths, the similarity of which in 

 the adult state is not easily explained 

 by convergence. Further, certain cases 

 of resemblance among insects, in which 

 the larvae differ but live in the same 

 localities, sometimes upon the same 

 plants, are difficult to interpret under 

 one or the other of these alternatives 

 which we have indicated (convergence 

 or poecilogony). We cite for example 

 Litliosia complanana and L. Inri- 

 deola^ Deilephila euphorbiae and D. 

 nicaea. 



Finally the only purpose in this short 

 note is to state a ver^' important 

 problem of general biology, touching 

 at once embryology, ethology and 

 taxonomy. Perhaps on certain sides 

 the problem is capable of experimental 

 solution. In any case the question 

 ought to receive light from our spe- 

 cialist friends, if they will study into the 

 numerous cases of the kind enumerated 

 above, wliich pass daily under their 

 eyes, and of which they, better than 

 any others, can state precisely the 

 actual value. 



In "The butterfly hunters in the Carri- 

 bees" (N. Y., Scribner) Mr. E. M. Aaron, 

 in the guise of a learned "Dr. Bartlett," takes 

 two boys of a friend coIlectin<; in the 

 Bahamas, Hayti and Jamaica, and brings 

 them back laden with spoil and honors, 

 culminating in their election into the 

 Philadelphia Academy. What with historv 



and other matters butterflies themselves play 

 a minor part, but there are some observa- 

 tions due to personal experience which lend 

 a certain value to the book. It ought to 

 interest boys, for it has the odor of the 

 camp about it, but we could wish there had 

 been less of the mercantile spirit in it. It is 

 well printed. 



