816 
GERYDUS. By H. Frithstorfer. 
and tibia together, the claws uncommonly small. The egg of the genus was discovered by Doherty who states 
it to be uncommonly flat, less than one third as high as it is wide. We owe the first figure of the egg to 
Kershaw from whose figure we see that it is of the shape of a folded Japanese paper lantern. 
We know about 17 species of mostly Macromalayan origin. Borneo is inhabited by 8, so is Sumatra, 
Java by 5, the Philippines by as many, Micromalayana by one species. The subregion of Celebes harbours 
2 distinct species, the Moluccas and New Guinea just as many. One species (G. boisduvali) has its range through 
the whole of Indo-Australia, from Sikkim as far as Dutch New-Guinea. Other species are very much localized, 
confined to one single island. 
2 groups of species: 
a) Without a thickened anterior median of the forewing. Archaeogerydus. 
b) With a thickened anterior median of the forewing. Gerydus. 
a) Group of species Archaeogerydus Fruhst. 
croton. G. croton Doll. So far reported from Pegu, the Shan States, and Tenasserim; I myself am able to 
verify its discovery in South Annam. above brown with a whitish band consisting of four spots, extending 
as a semi-bow beyond the cell as far as the submedian, croton- thereby resemble the $$ of certain races 
of G. boisduvali. Hindwings unicolorously brown. Under surface grey with a faint blackish basal spot and a 
mallus. repetition of the white band of the forewings above. - — - mallus Fruhst. (141 f). $ smaller than croton, of a duller 
brown. Band of the forewing yellowish-white, more strongly bent, consisting of smaller components. One 
A with four, one <$ only with three maculae. the macular series of the forewings more indistinct than in 
croton, in one specimen almost obliterated. $$ much smaller than the from the Plateau of Dran. 
Under surface whitish-grey, faded, only the angular median band of the hindwing distinct. The black Gerydus- 
spot of the forewing most prominent, only in one 2 it is fading, mallus belongs to an extreme dry-period form. 
Darker and more imposing examples may be found in Tonkin. The butterflies have an uncommonly swift 
flight, so that I did not know what kind of butterflies were dashing along past me on the Plateau of Dran in 
South Annam, at an altitude of about 1500 m. The Gerydus fly slowly and deliberately in the plains, but it 
seems that up on the mountains they are forced by the ever blowing, fierce winds to strengthen their flying- 
muscles and to adapt themselves to the new conditions, in what they have most amazingly succeeded. 
gethusus. G. gethusus spec. nov. Above unicolorously brown like G. gaesa (141 f), but with a similarly pointed 
wing-contour and also in the habitus of the size of G. boisduvali chinensis Fldr. On the forewings there are faint 
traces of a whitish band reminding us of G. croton. Under surface similar to that of G. boisduvali chinensis, 
but with still less rudiments of a subanal white area of the forewing. Tonkin, Chiem-Hoa, in August and Septem¬ 
ber, the beginning of the dry period, collected by myself in one male specimen at an elevation of about 500 m. 
G. learchus, hitherto known only from the Philippines, is distributed in a number of insular races 
also over Macromalayana, but the different off-branches were hitherto dealt with as separate species. There 
are forms with a white disc of the upper surface of the forewings in both sexes, and one-coloured brown forms. 
There exist transitions between them in North Borneo and its adjacent islands, but there is nothing certain 
published about them and the specimens being dispersed in some English Collections were not accessible to 
me. On the whole, the under surface resembles that of G. boisduvali (141 e), nor Mo the clasping-organs differ 
essentially from this widely distributed species. But the uncus-sheets of the Sumatran subspecies are shorter, 
broader, dorsally less deeply indented. The ventral small hooks are much thinner, also otherwise feebler, the 
valve considerably shorter, blunter, learchus is, like G. zinckeni Fldr. (141 e) and G. gaetulus Nicev., without 
a black basal spot of the under surface of the forewings. The presence or absence of this mark, however, is 
unessential, because there are already transitions in G. boisduvali and particularly in the females of the dry 
learchus. period form this macula occasionally disappears, learchus Fldr. Upper surface with a dull greyish-white 
discal spot. Under surface of the forewings a little lighter in the disc; hindwings grey. Luzon. Very rare, no 
philippus. more found since Felder’s times. Felder’s statement ,,Cochin“ has hitherto no more been verified. — philippus 
Stgr. (141 e) is a common form of the Island of Palawan. The white area of the forewing not darkened, in the 
$ rectangular, in the $ more like a disc. $ slightly differing from the <$ with somewhat more strongly dentate 
carrinas. hindwings. According to Moulton, an allied form occurs both in Labuan and in Borneo. - — - carrinas subsp. nov. 
is introduced here as a novelty for South Borneo. Habitus larger than that of gaesa ; the under surface appears 
darker and traversed by more prominent brown bands. Sintang, on the Kapuas River. Discovered by Dr. 
gaesa. Martin. To carrinas presumably belong examples mentioned by Moulton from Pulo Laut. — gaesa Nicev. 
(141 f). Upper surface unicolorously brown with traces of a whitish oblique band placed similarly as in 
G. boisduvali. Shape of the wings more roundish than in G. boisduvali, but the marking of the under surface 
