INTRODUCTORY PAPERS ON LEPIDOPTERA. 147 
brassy green band beyond the middle on all the wings ; towards the 
base they are darker green, intersected by numerous rather 
broad black lines. The under side of the hind wings is of some 
shade of red; sometimes spotless, and sometimes with transverse 
lines, and a submarginal row of black dots or rings. | They 
inhabit the west of South America, and Mr. Bates describes their 
flight as very rapid. 
Batesia Hypochlora, and its allies or varieties, are still larger 
and more splendid insects from the Upper Amazon and Ecuador. 
The fore wings are black, with the basal third blue, and a very 
large red oval transverse spot or band running from below the 
costa three-quarters of the distance to the hinder angle. The 
hind wings are blue above, with a submarginal and rather narrow 
black band; beneath they are olive-yellow, or greenish, with the 
submarginal black stripe narrower than above. I have no infor- 
mation respecting their habits. 
The genus Ageronia contains many common and well-known 
species from Tropical America. It was at first formed into a 
separate family, and was placed by Doubleday between the 
Pieride and Danaide, owing to an erroneous statement that the 
pup were attached like those of the Papilionide and Pieride. 
But Mr. Bates discovered that the pups were suspended by the 
tail; and Ageronia was then removed to the Nymphalide. The 
perfect insects frequent forests, and are remarkable for the crack- 
ing noise they make with their wings during flight, a peculiarity 
first noticed and recorded by Mr. Darwin. The butterflies 
expand from two to three inches; the fore wings are generally 
rather short, with the hind margin very slightly concave, and the 
hind margin of the hind wings slightly dentated. They are 
mottled with black, bluish, and white, and are sometimes marked 
with dull reddish spots; and there is generally a submarginal 
row of black eyes, with white pupils on the hind wings. Some 
species are velvety black above, spotted with blue; or very deep 
blue, spotted with paler, and with an oblique white band on the 
fore wings in the females. The under surface of the hind wings 
varies from pale silvery grey, with a row of submarginal brown 
rings, bordered on each side with a brown line, to yellow, red, 
brown, or steel-blue ; spotted with red in various species. 
The genus Didonis contains a few brown butterflies, expand- 
ing about two and a half inches, with the hind margin of the fore 
