March 10, 1899.] 



SCIENCE. 



373 



Consanguiueous marriages are not iu them- 

 selves, in perfectly healthy stock, causes of de- 

 generacy, but where degeneracy has begun, 

 such marriages, of course, accelerate its action. 



The book closes with a chapter on the pre- 

 vention and treatment of degeneracy. The 

 author is not an advocate of heroic methods, 

 such as the legal regulation of marriage and 

 other still more certain methods of checking its 

 transmission. He proposes milder means, par- 

 ticularly rational forms of prophylaxis adapted 

 to circumstances and to individuals. 



G. T. W. Patrick. 



University of Iowa, 

 Iowa City. 



A Synonymic Catalogue of the North American 

 Rhopalocera. By Henry Skinner. Ameri- 

 can Entomological Society, December, 1898. 

 Pp. xiv + 100. 



The catalogue of North American butter- 

 flies published by Mr. W. H. Edwards in 1884 

 listed 612 species from the United States and 

 Canada. The new catalogue, now before us, 

 enumerates 645 ; the moderate number of addi- 

 tions iu about 14 years of great activity among 

 lepidopterists indicates that our butterfly fauna 

 is fairly well known. The additions are in 

 reality somewhat more numerous than the fig- 

 ures cited indicate, owing to the rejection of 

 some of the names of the earlier list; but there 

 is no tendency to 'lumping' exhibited, which 

 is rather surprising in consideration of some of 

 Dr. Skinner's previously expressed views. 



The literature is cited very fully, though we 

 notice a few omissions, such as that of Edwards' 

 account of the larva of Lycsena exilis. The 

 genera are nearly as in the Edwards catalogue. 

 It is to be regretted that Pam.phila is still made 

 to include a great number of forms, belonging 

 to numerous genera ; but it is certainly true 

 that the best generic arrangement which could 

 be ofiered at the present time would be largely 

 provisional. 



An examination of the catalogue recalls and 

 emphasizes certain interesting features of our 

 butterfly fauna. Certain portions are of trop- 

 ical origin, while other groups belong to what 

 has been called the holarctic region. In the 

 tropics conditions have been relatively uniform 



for ages, and in consequence we have a large 

 number of organisms in a condition of consid- 

 erable stability — in other words, 'good species.' 



The writer has found, when working with 

 Coccidffl, that the tropical species are, as a gen- 

 eral rule, much more easily separated than those 

 of temperate regions. The same is true, ap- 

 parently, among the butterflies. Take the 

 Hesperidffi and LycEenidaj, which are so numer- 

 ous iu tropical America. The tropical groups 

 of HesperidiB, in particular, have largely in- 

 vaded the United States, and very many species 

 have been catalogued. Now Dr. Skinner him- 

 self has told us in another connection that 

 these species are, as a rule, well-defined, though 

 frequently superficially similar. But there is 

 one characteristically holarctic series of Hes- 

 peridse — the series of Pamphila comma — and here 

 at once we meet with innumerable local races 

 or weak species, with difficulty to be separated 

 from one another. So in Lycxna the holarctic 

 group of pseudargiolus and its allies is especially 

 polymorphic. When we come to the typically 

 holarctic genera, such as Argynnis, we find a 

 wilderness of plastic forms, which may be 

 called species or varieties according to the taste 

 of the student. 



It thus happens that for the evolutionist 

 temperate regions, lately subject to glacial 

 desolation, are in many respects more interest- 

 ing than the luxuriant tropics. Here, especially, 

 are species in the making ; here is Nature's 

 kitchen and the cook at work. In the tropics, 

 on the other hand, we often find more numerous 

 and more finished products, and wonderful 

 adaptations, the origin of which is past our 

 comprehension.* The naturalist in South Amer- 

 ica might well think species were created as 

 he found them ; the naturalist of the northern 

 United States could hardly imagine such a 

 thing, unless convinced on a priori grounds. 



Yet when changes have occurred in tropical 

 lands we find such phenomena as are common 

 in the north. The snails of the Greater Antilles, 

 islands that have undergone great changes of 

 level in recent geological periods, are almost as 

 confusing as the North American Argynnids. 

 So, it seems, we may in some measure learn the 



* For plants compare Dr. E. Warming's interest- 

 ing paper in the Botanical Gazette, January, 1899. 



