416 DR. J. C. MOTTRAM ON 



present, would, however, tend to mask the outline. As to whether 

 or not these insects are conspicuous in Nature must depend upon 

 the tone of the backgrounds against which they are commonly to 

 be seen ; if the backgrounds be light in tone they would be 

 conspicuous insects, but if the insects lived in dark forests, for 

 instance, they would not be especially conspicuous. 



No. 11 is similar to the last except that both wings present a 

 large white patch which must make the insect more conspicuous. 

 The patch on the fore wing interrupts the antei-ior margin and 

 must therefore have the opposite eft'ect. 



No. 10 presents a black-centre white-margin pattei-n wliich, as 

 has been seen, is almost as conspicuous as the white-centre black- 

 mai-gin pattern. 



Nos. 4, 6, IS, cfe 14 present patterns which do not interrupt 

 the margin but, instead, follow it ; there are three central bands 

 or rows of spots which are surrounded by black, and the margins 

 of the wings are not scalloped, thus several factors making for 

 conspicuousness are present. 



In no. 1 the pattern everywhere interrupts the margin, and the 

 margin of the wing is not scalloped. The pattern is not tlierefoi'e 

 a conspicuous one, the general tone of the insect is light and the 

 wing-expanse large ; thus, in spite of an inconspicuous pattern, 

 the insect might be conspicuous if its natural environment were 

 of dark tone — if, for instance, it Avere a foi'est insect. It may be 

 noted that another species of the same genus (see text-fig. 20, 4) 

 presents a typical conspicuous pattern. 



No. 15 presents no character making for conspicuousness ; the 

 margin is somewhat scalloped, the pattern interrupts the margins, 

 the insect, as drawn, is coloured a middle brown with a darker 

 line pattern, and is mimicked by Eolimia joarisatis. With the 

 exception of this genus and Hestia, the patterns of these pro- 

 tected or mimicked insects all show one or more characters 

 which make iov conspicuousness, and present patterns much less 

 perfectly conspicuous than the two types first dealt with. The 

 first tyjDe conforms very closely to the pattern which experimental 

 consideration indicates must be the most conspicuous. Even the 

 larger proportion of black to white tone in the pattern conforms ; 

 as the backgrounds in Nature are for the most part dark rather 

 than light in tone, so there should be a greater proportion of 

 white to black in the pattern. It is not possible to show why 

 less perfect types are to be found ; perhaps they present a stage 

 in the evolution of the conspicuous patterns, or that for some 

 reason a more perfect pattern is not required by these insects. 

 •On referring to text-figs. 17 and 18 it can be seen that the 

 mimicking species present patterns which are not so perfect as 

 the models. Acidalia, for instance, could with justice be removed 

 from the first series. 



As a contrast to these patterns four inconspicuous patterns are 

 shown in text-fig. 20, 1, 2, 3, 5 ; it can be seen that in three the 

 margin is scalloped ; in nos. 1 and 3 the pattern interrupts the 



