Whittock, Nathaniel: The Art Of Drawing And Colouring, From Nature, Birds, Beasts, Fishes, And Insects: With Plain And Coloured Drawings, From Original Paintings By Morland, Vernet, Howet, Le Cave, &c. (London, 1830)

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with pure black, and glaze down the light and middle tints with
prussian blue, if they are too prominent.
The tiger in Lesson XVII. is a good subject for the comb, as the
hair of this animal is very strong and wiry, and the comb will blend
the dark stripes among the light parts of the coat of the tiger; it will
also be found effective in the hair round the head.
In the following Lesson, the method of producing the sky in oil
colours will be found an important addition to the directions already
given.

LESSON XXI.
LIBELLA, OR DRAGON FLIES.
Buffon observes, that of all the ssies that adorn or diversify the face
of nature, these are the most various and the most beautiful; they are
found of all colours, but those commonly seen in England are the
large yellow, or the bright blue dragon ssy; and, as they are most
easily obtained, they are selected as the subject of this lesson.