77 
arrangement as one, the attainment of which was regarded (if we may- 
use such language) as an object of ambition by the earliest Lepidoptera, 
which as yet possessed freedom of movement of a majority of their 
abdominal segments, and in which the 7th was still movable in the 
male although not in the female pupa. Setting off along several 
different roads, the structural arrangement mentioned above has been 
arrived at more especially by the Macro-Heterocera. Whether it has 
been reached by one or more routes I am not at all certain, but I am 
disposed to think that amongst the Bombyces will be found groups that 
have attained this condition of development independently of one 
another; I am not at all sure that the Pyralides do not represent a 
separate line ; but, at any rate, it seems certain that the butterflies have 
taken an entirely independent route. 
Like the pupa of the Macro-Heterocera, that of Papilio (Figs. 
1,2) has got rid of nearly all “ Micro ” features; there is no dorsal 
head-piece; there are no maxillary palpi; the antennae separate from 
the head-piece on dehiscence ( i.e ., when the imago emerges); only the 
5th and 6th segments are free, and these possess the power of move¬ 
ment in all directions. There are, however, two earlier features 
retained by the Papilionids which the Macro-Heterocera have lost; one 
of these is the possession of a waist, caused by the narrowing, chiefly by 
dorsal depression, of the last thoracic and 1st and 2nd abdominal 
segments; the other is a certain amount of opening, on dehiscence, of 
otherwise solidified incisions, which is observed in some species. There 
is another noticeable difference which may possibly be associated with 
the retention of these early features; the Papilionid pupa is capable of 
further evolution, as evidenced by the fact that additional features 
appear as we pass from it to the higher families, whilst the “ Macro ” 
pupa among the Heterocera seems to be a terminus not yet at least 
over-passed ( Spilosoma may seem to be an exception). 
Ephyra Zonosoma is interesting as an illustration of the fact that habits 
and structure very nearly identical may be reached by quite distinct paths. 
Just as the pupa of Papilio is, in its general structure, nearly identical 
with that of one of the Macro-Heterocera, so that of Ephyra comes 
even closer still to that of Papilio, with which it is nearly identical in 
general form and in manner of suspension. Yet it is as nearly certain 
as anything of the sort can be, that we must go back as far, or nearly as 
far, as Hepialus to find a common ancestor. Wherein then does the pupa 
of Ephyra differ from that of Papilio ? It is smooth and rounded; still 
it has a well-developed ridge near the inner margin of the wing similar 
to that in Papilio, and this is very unusual in a Geometer pupa. This 
ridge originates at an anterior spine that, in Papilio, usually gives off a 
ridge to the middle of the wing, the inner marginal ridge starting from 
a spine situated farther back. Yet there are pupae of Papilio in which 
there is little or no trace of the ridge running to the centre of the wing, and 
in which the two spines are connected by a ridge ; whilst in Ephyra there 
is a slight break, as if a posterior spine could be distinguished. But 
there are points of difference between the pupae which seem to be quite 
distinctive ; the first of these is the entire absence in Ephyra of any 
nose-horn; a second, that the girth is not incorporated in the pupal 
case across the dorsum; thirdly, in Ephyra a portion of the femur is 
seen between the maxillae and the first pair of legs, whilst between the 
apices of the wings the tips of the antennae, together with the ex- 
