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SCIENCE 



[N. S. Vol. XXVII. No. 684 



most remarkable. The seeming double-brood- 

 edness of L. decem-lineata may be due to the 

 difference in the time of emergence from 

 hibernation of different individuals. We 

 have no exact data regarding this point in 

 L. decem-lineata, but some very pertinent ones 

 on the boll-weevil which elucidate this subject. 

 In Bulletin 51 of the Bureau of Entomology, 

 p. 108, it is shown that the boll-weevil con- 

 tinued to emerge from hibernation during a 

 period of more than two months (March 18- 

 May 26). It is only reasonable to suppose 

 that there would be an equal irregularity in 

 the time of copulation, oviposition and larval 

 development — amply sufficient to account for 

 the two apparent broods. 



Lepiinotarsa juncta is taken up on page 49, 

 and its retreat before decem-lineata discussed. 

 The original distribution of juncta, as given 

 in the text and on the accompanying map, is 

 incorrect. Originally the species extended 

 along the Atlantic as far north as the New 

 England states and west of the Alleghenies 

 at least northward into Ohio. As to the pres- 

 ent distribution, I know of its recent occTir- 

 rence at Eichmond, Va., New Eichmond, O., 

 and St. Louis, Mo. The observation of Pro- 

 fessor Quaintance that juncta and decem- 

 lineata " hybridize freely in nature, although 

 the eggs that are laid are not fertile," is in- 

 geniously turned to accoiint. 



" The full explanation of the extinction of 

 juncta is to be found in the fact that the two 

 species cross freely in nature, and that this 

 natural crossing has resulted in a most in- 

 teresting and peculiar case of prepotency in 

 one species and of submergence in the other." 

 In other words, according to Tower, L. juncta 

 in crossing with decem-lineata has been elim- 

 inated through Mendel's law. Does Tower 

 realize that juncta has a number of specific 

 characters and that these can not all be " re- 

 cessive " — at least not according to the usual 

 interpretation of the Mendelian law ? In fact, 

 juncta continues to exist as a distinct species, 

 even upon the same plant with decem-lineata. 

 Purthermore, Tower states (p. 20) that his 

 L. ohlongata and L. multitmniata Stal occur 

 together upon the same food plant but do not 

 interbreed. The same statement is made with 



reference to L. multitmniata and L. rubicunda 

 Tower. These three forms appear to be much 

 more nearly related to each other than are 

 L. decem-lineata and L. juncta and it is un- 

 reasonable to believe that the last two inter- 

 breed freely while the first three do not. A 

 similar case to that of these two species of 

 Leptinotarsa is that of the crowding out of 

 Pieris oleracea by Pieris rapce. Pieris ole- 

 racea still persists in the mountainous parts 

 of New England, where it is found associated 

 with P. rapce, and it would be going far afield 

 to invoke the " recessive " principle of Men- 

 del's law to explain its disappearance from its 

 former territory. In the Chrysomelidse the 

 crossing of closely related species is quite com- 

 mon when the two forms occur upon the same 

 food plant. I have observed it repeatedly in 

 Gastroidea polygoni and G. cyanea, but I am 

 not aware that such crossing has had any ap- 

 preciable effect upon either species. 



In the chapter on the habits and instincts 

 of Leptinotarsa we find, on page 236, the fol- 

 lowing statement: "the eggs, although they 

 may be fully formed and fertilized, are not 

 laid, but are retained in the passages of the 

 female reproductive organs until they are re- 

 sorbed, or, as more frequently happens, until 

 the female dies." As the process of egg fer- 

 tilization in insects is generally understood, 

 the seminal fluid is deposited in the recep- 

 taculum seminis and the eggs are only fertil- 

 ized when they pass this organ during ovi- 

 position. 



The statement, on page 260, that all the 

 species of Leptinotarsa feed upon Solanaee89 

 is certainly incorrect; this may be true of the 

 lineata group, but it is certainly not for the 

 whole genus. 



Chapter III., which deals largely with the 

 physiology of color-pattern production, is the 

 most scholarly part of the work, and most in- 

 teresting and instructive. It is, however, in 

 great part a repetition of the previously pub- 

 lished investigations of the author. 



Many pages of the book are taken up with 

 tables which look very impressive. As the 

 figures are, however, for the most part only in 

 averages, and there is nothing to show how 

 extensive or complete are the data back of 



