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concentration of the broader band of pupal tissue specially 
prepared to meet the pressure when it first became a danger. 
Comparison with the pup of some of our common British 
Geometrz supports the hypothesis set forth above; for it is 
seen that very similar changes have independently occurred, 
and occurred so recently that the essential stages are still 
preserved. Furthermore, they are invariably met with in 
species which have a short pupal period passed in the warmer 
months of the northern year. Hugonia quercinaria spins a 
loose and open cocoon, within which the chrysalis, as well 
as the larva before pupation, develops an effective cryptic 
colouring.* Both larva and pupa are freely exposed to 
view through chinks in the scanty network and between 
the imperfectly united leaves. Uvropteryx sambucaria con- 
structs a slight hanging cocoon, affording very little con- 
cealment. The enclosed pupa bears a marked cryptic 
appearance, while the only experiment which has been made 
indicates the possibility of a well-developed power of individual 
colour adjustment.t Both these species, and especially the 
last, have long since reached the stage at which the reduction 
of the cocoon became advantageous. In the genus Zonosoma 
(Lphyra) we independently arrive at the same climax of reduc- 
tion attained in the Pierinz, etc., the cocoon being represented 
by a supporting loop and the means of fixation of the posterior 
extremity.{ No search has been made, so far as I am aware, 
for a special strengthening of the cuticle upon which the loop 
presses, but it is probable that nothing of the kind is required 
by these small light pupe. The exposed Ephyrid chrysalis 
is fully as cryptic as that of the average butterfly, but it 
lacks the power of colour adjustment. When the Ephyrid 
larva is dimorphic, green or brown, the colour of the pupa 
corresponds to that of the larva from which it developed.§ 
* Trans. Ent. Soc. Lond., 1885, p. 319. 
+ See ‘Colours of Animals,” London, 1890, pp. 111, 112. Only one 
example was placed on white paper before pupation. Although the 
resulting chrysalis was very pale and strikingly different from the ordinary 
appearance, the evidence is quite insufficient, and it is much to be hoped 
that the experiment will be repeated upon a large scale. 
+ Trans. Ent. Soc. Lond., 1884, p. 57. 
§ Trans. Ent. Soc. Lond., 1884, p. 51; Phil. Trans. Roy. Soc., vol. 
178 (1887), B., pp. 487, 438. 
