172 The Irish Naturalist. [August, 



This species usually appears in the evening about 15 m. 

 after sunset, being about 10 m. earlier in the spring and 10 m. 

 later in the autumn. 



At first it commonly flies at a considerable height, in open 

 country taking long sweeps and wide zigzags, often being 

 seen but once in an evening. Near woods and in favourable 

 localities it will often remain for some little time near one 

 spot, flying at an altitude of 30-40 feet, with a faster and 

 less irregular flight than the Pipistrelle, the tail being 

 extended in a straight line with the body. L,ater on it flies 

 nearer the ground, very commonly shrieking loudly, and I have 

 observed two bats at this time chasing one another exactly as 

 two butterflies do, both flying very fast and screaming. 



As far as I can ascertain — the point is difficult to determine 

 — the Hairy-armed Bat flies for about an hour, and then 

 retires, not to reappear till the next evening. 



1 have not been fortunate enough to come across any of the 

 resting-places of these animals, so that the times given above 

 are only approximate, being taken from observations made in 

 the open. Still, making every allowance for error, the facts 

 are sufficiently remarkable. A mammal, that rests for six 

 months in the year, that only feeds for one hour a day during 

 the other six, spending this hour in rapid and sustained 

 flight — as great a contrast as can be imagined to its previous 

 condition— certainly presents a very curious picture of animal 

 economy. 



This species would appear to be wholly insectivorous. 

 Mr. G. H. Carpenter's researches on the fragments found in 

 the stomach after death show that Diptera form the great bulk 

 of the food, and he has been able to identify a midge, probably 

 a Mycetophilid, an Acalypterate Muscid, and the yellow-haired 

 fly, Scatophaga stcrcoraria, already referred to, besides legs and 

 wings of caddis-flies. Scales of moths were plentifully found 

 in one case. This bat furnishes therefore an interesting 

 contrast to the Noctule, the latter feeding on species of 

 beetles. 



The Hairy-armed Bat has been found in colonies inhabiting 

 hollow trees and roofs of houses, as in the case of Mr. R. M. 

 Barrington's specimens, but most of the captures have been 

 of solitary individuals either in the open or in rooms into 

 which they have flown. 



