320 Dr. Frederick A. Dixey on 
latter bar is indicated, the chestnut-coloured streak takes 
no part in its formation; in P. leptalina, however, the 
same chestnut-coloured streak is better pronounced along 
the hind margin than in P. pandosia, and is prolonged 
for a short distance along the transverse bar (fig. 2, 0). 
In this way a considerable resemblance is brought about 
between P. leptalina and some of the well-known trans- 
parent neotropical Danainz, which are presumably 
protected, such as Napeogenes inachia (fig. 4). It is 
worth noting that the bar 0, which belongs to the hind- 
wing in P. pandosia and P. leptalina, appears to 
represent the dark inner margin of the forewing in the 
model; and the presence upon its distal portion in P. 
leptalina of a sight prolongation of the chestnut marginal 
streak may perhaps stand for the turning inwards of the 
corresponding chestnut marginal band in N. inachia 
along the costal border (figs. 2 and 4). 
4. The “numata” line. This series needs here no 
more than a mention, as it has been already discussed 
and illustrated in the paper above referred to.* 
5. The “tarracina”’ line. This is an offshoot of the 
last, or nuwmata line, diverging in the neighbourhood of 
Mylothris malenka § , or perhaps somewhat further back 
towards the original Pieris. ‘The remarkable form M. 
alethina § shows a near approach to the pattern of 
Tithorea tarracina and other associated species; its own 
aspect being probably derived from a type like M. lorena 2 
or M. malenka 2 , in which the yellow of P. demonhile ? 
has persisted, and the base of the forewings has become 
overspread with black.t+ 
General Considerations. There is, therefore, in each one 
of these cases, a continuous line to be traced ; starting 
in every instance from the same ordinary Pierine form, 
and passing through a graduated series of closely-allied 
* Vide supra, p. 319, note. 
+ Three at least of the above five lines of development, viz., 
the agna, the numata, and the inachia lines, can be paralleled from 
the genus Désmorphia and its allies, and it is interesting to see in 
the latter case how the same ultimate result is brought about by 
somewhat different means. But I have not attempted to include 
species of Dismorphia within the above series, because the affinity 
of this genus with Pieris and Mylothris is not close, and its own 
course of mimetic development, so far as phylogeny is concerned, 
must be regarded as completely independent. 
