xlix 



volume of Dr. August Weismann's ' Studien zur Descendeiiz 

 Tlieorie,' Leipzig, 1876, large 8vo, with five coloured plates; the 

 first division of the memoir being entitled " Ontogenese und Mor- 

 phologie der Sphingiden-Zeichnung," and the second division 

 " Ueber den Phyletischen parallelismus bei metamorphischen 

 arten." The first four plates illustrate the variations in the 

 colours and marks of the larvae of the Sphingidte, and the fifth 

 those of Saturnia Carpini, one or more segments of the body in 

 different specimens and varieties being represented : 225 pages of 

 small print are occupied in the discussion of this subject, to which, 

 as appears to me, far too much importance has been attached. 



Every fact, however, bearing on this curious question deserves 

 to be carefully investigated, even if it extend no further than the 

 darker or lighter colour of certain broods of insects. In this country 

 Lycsena Artaxerxes offers a curious instance of this subject. 



It is, moreover, well known that in certain localities, especially 

 in the northern parts of England and Scotland, certain pale- 

 coloured moths assume a darker coloration, and thus, as we learn 

 from an article on " Melanism," by Mr. Edwin Birchall, F.L.S. 

 (Entom. M. Mag., November, 1876, p. 131), near Leeds, Aplecta 

 nebulosa and Xylophasia polyodon are often perfectly black, and the 

 "black pepper" {Blston betularia, var.) is well known, although, as 

 described by the late R. S. Edleston in ' Newman's Entomologist * 

 (ii. p. 150) sixteen years previously, it was almost unknown near 

 Manchester. The dark variety had, however, so much increased 

 subsequently that he considered the original pale type of the 

 species would soon be extinct in the locality. Mr. Birchall 

 speculates {sensu Darwiniano) on the causes of the melanism, and 

 gives a list of the species of moths of which melanic varieties occur 

 in the northern and western parts of the British Islands. The 

 subject has been, however, carried much further by Dr. F. 

 Buchanan White (Ent. M. Mag., December, 1870) by whom the 

 430 (or thereabouts) species of Macro-Lepidoptera inhabiting 

 Scotland are subjected to an analysis in this point of view ; the 

 majority appearing not to exhibit any decided variation. Certain 

 species, however, offer variation in any locality. The remaining 

 species are thus divided : — 



A. Melanochroic species. 



1. Melanochroic races (amongst which it is remarkable that 

 the extreme northern form of Aplecta occulta is pale). 



H 



