98 A RAMBLE UP BURNHOPE. 



stroke of the net secured an Eristalis, which uttered its little 

 pitiful cry for release. Often has that cry made me inclined 

 to let my captive go, although I wanted it as a specimen. 

 My net-bags are closed with a circular piece of celluloid, 

 against which I gently pressed the under side of the fly, so as 

 to look into its mouth. All motion of the wings was pre- 

 vented by the closely pressed folds of the net, yet the fly 

 continued to emit its little cry at intervals. On looking into 

 its mouth with the pocket lens I could clearly see something, 

 it might be the end of the palpi, vibrating rapidly whenever the 

 cry was repeated. It seemed to suggest that the sound was the 

 result of vibration, set up by expressed air, as in mammals. 

 But where does the air come from ? Flies have no air-bags 

 communicating with the mouth, like the lungs of beasts. 



But I will never get to my destination up the dale if I stop 

 to solve these fly problems here. So, forward. 



However I had soon to stop again. Just above the flowery 

 Dank the sides of the stream became more rocky, and on its 

 shady southern bank they were almost precipitous, the sand- 

 stone all broken up into shelves and cracks, in whose nooks 

 and crannies there flourished a rich growth of mosses and 

 ferns. There was that common but beautiful moss, M7iium 

 undulatutn, Hed., which long ago I used to pounce upon as a 

 prize, in a district where the Filmy Fern ( Hymenophyllum 

 TiDibrigense, L.) was to be found, though not at all common. 

 At first sight there is a strong resemblance between the two, 

 but it is only at first sight, and to a very inexperienced eye. 



Two other Mniums were growing near. Hunting about 

 among the clefts I came upon a darkish-green moss, with very 

 distinct roundish leaves, which I knew to be M. punctatum, 

 Hed., and I was pleased to find a number of the long-stalked 

 capsules still remaining, some indeed quite green. A few feet 

 away was quite a cushion of the starry heads of the male 

 plants, with their brown chaffy centres surrounded with their 

 four red-veined leaves. And near the edge of the stream, on 

 the moist banks, were dense cushions of M. hornunif L., its 

 leaves erect and pointed, and with doubly serrated edges. 



