88 Mammals of Eastern Asia 
European Noctule, N. noctula, but those of the East are very 
similar. They comprise two groups : the first group, N. lasiop- 
terns aviator, from off the mouth of Yangtse River and from 
Japan; the second group, N. noctula motoyoshii also from 
Japan, N. plancei (sinensis) from Hopei, Hunan, and Szech- 
wan, and N. velutinns from Fukien, Chekiang, Hupeh, and 
Kiangsu. The first is a large species with the forearm 2% 
inches long; the others are smaller, with forearms only about 2 
inches long. N. labiatus from Nepal, northern India, though 
nearest in size to N. noctula, appears to be aberrant. The distri- 
bution of the Noctules is chiefly subtropical. They are unknown 
in the New World. 
Nyctahis velutinus is reported to hide by day in the hollow 
joints of bamboo that birds may have drilled. Nyctalus noctula 
lives in forests, hiding during the day in groups in old hollow 
trees. Although it flies high at night, it has been observed by 
day flying low over water. It is reported by Ognev to eat num- 
bers of cockchafer beetles, diving upon them while they are 
on the wing. Either 1 or 2 young are born. There is evidence 
to show that in Russia these bats assemble in flocks and migrate 
as some birds do. 
The la Bat, la io, is a blackish brown Bat with the outward 
appearance of a Nyctalus. The pair of two-letter words which 
form its name were bestowed by a scientist momentarily exas- 
perated at long technical words. Io was a Goddess of Greek 
mythology. Because she and Zeus became too friendly, Hera, 
Zeus's wife, changed her into a heifer. As for la, we suspect it 
was just invented. 
Aside from its name, la io is a fine large Bat with the fore- 
arm a shade less than 3 inches long. It is found in Hupeh and 
Szechwan, and has been recorded from a cave at Chiengo Dao, 
on the Mekong River, northern Siam. 
The Barbastelle Bats, genus Barbastella (Fig. 12), are 
small, blackish brown Bats with pale underparts and short, thick, 
