142 B. p. UVAROV. 



My studies show, on the contrary, that the male genitaha of danica and migratoria, 

 which are composed of several very complicated pieces (see fig. 1, A, B, C, D), are 

 rather constant in the shape of the different parts, and though slight variations do 

 occur, these are in no way connected with the external differences, and afford no 

 reliable criterion for separating the two forms. 



Colour Characters in Adults and Larvae. 



In regard to the general coloration, as well as the pattern of the different parts, 

 adults of both danica and migratoria are rather variable, and no definite colour 

 characters can be given for separating them. Generally speaking, however, the 

 extent of the colour variability in migratoria is far less than in danica, and there 

 is a well-marked tendency in the former to a paler general coloration and less defined 

 markings ; especially noteworthy is the fact that the hind tibiae in migratoria are 

 never red, save quite exceptionally. 



The coloration of danica is generally far more variable, with the evident prevalence 

 of bright green forms ; dark brown, even almost black forms occur also not 

 infrequently, while the pattern is very variable but always well pronounced. The 

 hind tibiae in danica are very often red, but this character is far from being constant, 

 since often quite typical specimens have the hind tibiae pale or greenish. 



While, as above stated, the coloration of the adults is of but very little use for 

 separating the two forms, it is quite otherwise in the case of larval stages, in which 

 there is a very striking difference. In fact, it is almost impossible to find any definite 

 type of coloration of the larvae of danica, which vary enormously ; uniformly green 

 forms are most common, but fawn, grey, brown, and even black ones may be met 

 with together. Quite the opposite is the case in migratoria, in which each larval stage 

 exhibits quite constant colour characters. Their coloration presents a combination of 

 black and orange-red (or yellow), the earher stages being almost entirely black, 

 while orange, or yellow, appears first in the third stage, extending gradually after 

 each subsequent moult.* There is, of course, a certain variability in the shade of 

 the colours, but as a rule larvae of migratoria of the same stage are all practically 

 identically coloured ; and it is important to note that this type of coloration never 

 occurs in the larvae of danica in spite of the wide range of variation in the latter. 



Sexual Dimorphism. 



There is a well-pronounced sexual dimorphism of the general dimensions in 

 danica, the males (adults) being distinctly smaller than the females ; average figures 

 of the length of the body, elytra, etc., for males differ from corresponding figures for 

 females by about 20 per cent, of the latter, so that one may separate the sexes by the 

 size only, provided that the specimens are all taken at the same place and time. 

 As for the proportions between the dimensions of the different parts of the body, 

 they are not connected with the absolute dimensions and remain the same in 

 both sexes. 



In migratoria no such apparent difference in size between the sexes is observed, 

 the males being on the average smaller than the females by only some 4 per cent, of 

 the figures for the latter ; and males of larger size are indistinguishable from females 

 so far as the dimensions are concerned. Since the absolute dimensions in both 

 migratoria and danica, especially in the latter, are rather variable, they are of very 

 little value for separating these forms. 



* I do not propose to give a detailed description of the larval stages of migratoria, since this 

 has been done more than once by different authors ; very good descriptions and fairly good 

 coloured figures have been given by H. C. Pratt (Dept. of Agric. Feder. Malay States, Bull. 

 No. 24, 19f5). 



