REVIEWS. 
83 
general,” but contains very little information, merely stating that many 
of our native species are very beautiful, though^ not rivals to the tropical 
species, and alluding to the interest excited by the fact—no less wonderful, 
truly, for being known to most—that the transformations of butterflies are 
but successive rejections of its outward skin by an animal always one and 
the same in all stages of its existence. 
The general characters of the Imago are treated of in section third, which 
contains an outline of the principal features of their external anatomy, and 
the general structure, neuration, and clothing of the wings, with much 
interesting information about the scales, especially those recently disco¬ 
vered to be peculiar to the males of various species of Diurna, belonging 
to the genera Pieris, Argymnis, Hipparchia, and Polyommatus, and “ chiefly 
found in those species of which the males have the upper surface of the 
fore wings ornamented with patches of velvet-like hairs.” Several figures 
of these “ male scales” are given in the second of the two elementary 
plates, and are very curious. In the close of the section, Mr. Westwood 
observes, that the variations in the flight of the different species and 
tribes have been as yet but slightly investigated. We should be glad to 
see more attention paid to this subject, as it may not improbably prove of 
considerable value, and it is difficult to see why a well-defined variation in 
the modes of flight should not be as important as a difference of structure, 
on which, indeed, such variations often depend. It may probably be 
pretty safely affirmed that no two species of our native Diurna have 
exactly the same kind of flight; and a careful observation and record of 
then’ variations would be at once interesting and instructive, and would, 
at any rate, save the young collector the trouble of many a laborious 
chase, ending in fruitless capture. We speak from experience and the 
memory of past years. 
Section four is devoted to “ the preparatory states of Diurnal Lepidop- 
tera,” giving a general sketch of the progress of the insect from the egg to 
the imago, illustrations of which, from Sepp and Herold, are found in 
elementary plate B. 
Section six is a description of the two elementary plates, consisting of 
details of the perfect and preparatory states of butterflies, and forming an 
important and valuable addition to the work. 
“ In this introduction,” says Mr. Westwood, 11 1 have embodied the 
results of a very minute and microscopical examination of a vast number 
of species, which had been rendered necessary for my completion of the 
great work on the genera of Diurnal Lepidoptera, commenced by Mr. 
Edward Doubleday, and in which several important characters, hitherto 
