WAITE : VERTEBRATES OF THE WESTERN AINSTY. 83 
Respecting the Reptiles and Amphibians, the only matter which 
calls for remark is in connection with the Viper. I am not at all 
satisfied that it occurs im the district, although I know that it has 
certainly been taken south of the Wharfe. 
The Pisci-fauna of the Nidd and the Wharfe are very similar, and 
what differences exist may be attributed to the distinctive character 
of the two streams. Being somewhat sluggish, the coarser fish pre- 
dominate in the Nidd. ‘The reverse is the case in the Wharfe, no 
doubt due to the fact that it is a much clearer and faster-flowing river. 
It is worthy of remark that formerly the Wharfe, between Harewood 
and Tadcaster, was very rich in Trout, but of late years this fish has 
diminished in numbers and given place to the Grayling. So that now 
the Wharfe within the district must be regarded as a Grayling rather 
than as a Trout stream. 
MAMMALS. 
' Plecotus auritus (Linn.). Long-eared Bat. Not uncommon 
in the district ; it occurs at Wilstrop and Thorp Arch and is 
frequently found by the workmen when pulling down old cottages 
and farm buildings. Examples have also been obtained at 
Wetherby. 
Vesperugo noctula (Schreb.). Noctule. Great Bat. Fairly 
common, far more so than /. aurifus and especially so at Thorp 
Arch where it frequents the crevices in the Magnesian limestone 
rock known as Jackdaw Crag on the south side of the Wharfe. 
It has also been observed at Tadcaster and Boston Spa. This 
bat usually flies very high. 
I have several times kept this as well as other species of bats 
in captivity and have noticed a peculiarity which I have not 
seen described in print. When the Noctule goes to sleep the 
ear is thrown forward, the front edge then covers the eye and at 
the same time the aural aperture becomes enlarged. 
Vesperugo pipistrellus (Schreb.). Pipistrelle. Common Bat. 
This species is extremely abundant and generally distributed 
throughout the district. On a fine summer’s evening they may 
be seen flying by scores over the Wharfe. They frequent most 
of the church towers in the district, but the principal colonies 
are * ee found at Jackdaw Crag. 
e found the Pipistrelle feeding very largely upon the 
nea Swift Moth (Hepialus humuli) trom which it clips the 
wings. I have also noticed it taking the Magpie Moth (déraxas 
srossulariata) and the Swallow-tailed Moth (Urapteryx sambu- 
ape dl all of which are common in the district. 
March 18 
