CURIOSITIES OF METAMORPHOSIS. 157 
a certain and definite stage— that stage being determined by 
hereditary peculiarities. 
The metamorphoses of the Hydrocampidce are very interesting, 
on account of the extraordinary change which occurs in the con- 
dition of life between a swimming larva and a gay moth, to which 
water is almost certain death. The examples of the corresponding 
transformations of the gaily-coloured flies that lead aquatic exis- 
tences in the larva state naturally rise up before us, as also do 
the Zoea of the crustaceans, and all these peculiarly allied forms 
become more strongly than ever united in a common ancestry. 
FEMALE AND male MOTHS OF Climatobia bvitmata. 
Retrograde metamorphosis, that is, a transformation which, 
when completed, leaves the insect less elaborately organised than 
before, is observed in the females of Psyche and Orgyia , and 
several other genera. The female of the Winter Moth has no 
wings developed, that of Climatobia brumata has very small 
wings, and Psyche is not much more than an egg-bag, not having 
even the locomotive power of the caterpillar. Why the male 
should undergo a progressive metamorphosis, and receive addi- 
tional organs in the usual manner, and why the female, on the 
contrary, should positively retrograde in its evolution, is impos- 
sible of explanation at present. There is no evidence to prove 
that a difference exists in the caterpillars which turn eventually 
to the male and female moths, and all of them partake of the 
same kind of food. The legless and wingless females of Psyche 
are, perhaps, more retrograde than those of Orgyia. The females 
of Fumea and Hibernia have legs and antennae, and, therefore, 
their development is in excess of that of Psyche. 
It has been mentioned that the females of a genus of the 
