NOTES ON THE DRY SUMMER OF 1896. l73 



June, the colour of the woods changed rapidly from the delicate 

 tints of spring to the sicklier hues of autumn. So obvious was 

 the change that the fall of the leaf was expected. For this 

 peculiarity, extensive observations suggest an explanation. 

 Admittedly, the several weeks of blazing sunshine, with the 

 absence of rain, must have told seriously on trees, no less than 

 on lowlier forms of vegetation ; but the prevalance of Aphides 

 ("plant-lice") was a more potent factor in the change of the 

 leaves from a spring to an autumn colour. From their expansion 

 in May to the time when the above-mentioned changes became 

 apparent, the leaves of all trees, without exception, were 

 smeared with a thick layer of the viscid "honey-dew," which 

 fell from the secreting organs of the Aphides. This prevented 

 the normal movements of the stomata or breathing-pores. 

 Transpiration, as necessary to plants as is respiration to human 

 beings, was interrupted ; disorganisation of cell-contents ensued, 

 manifesting itself in a change of colour from chlorophyll-green 

 to shades of yellow, red, and brown. 



Before passing on to more important matters, it may be 

 well to notice the scarcity of a few kinds of insects. Not once 

 during the whole of the season did I see the clouded yellow 

 butterfly or the painted lady ; and half-a-dozen specimens will 

 include all that I saw of the silver-washed fritillary ; green- 

 veined whites were also far from abundant, and even such 

 common forms as the large and small cabbage white, tortoiseshell, 

 red admiral, and copper were fewer in number than we are 

 accustomed to see. 



A yet more interesting circumstance has to be related. Not 

 only in the Kennall Valley, but wherever my rambles have 

 taken me, I have searched the furze and heath in vain for that 

 object known to the country mind by such names as frog's spit, 

 toad's spit, and cuckoo's spit, and which the naturalist designates 

 the frog-hopper {Aphrophora spumaria). If others have 

 recollections of any recent summer when a five-mile walk could 

 be taken without coming across those familiar patches of froth, 

 their experience differs from the writer's. Read in conjunction 

 with what will be said later (about one or two other insects 

 which are also protected by a secretion of their own) this total 



