982 



THE NATURE BOOK 



backed, and its flesh-coloured feet and 

 legs mark it off from the Lesser Saddle- 

 backed. In full plumage the whole head, 

 tail and body colour of these three Gulls 

 is white, as is also that of the Common Gull 

 and Kittiwake, which, eighteen and six- 

 teen inches long respectively, have both 

 grey mantles, but the so-called Common 

 Gull has greenish-yellow feet and legs, 

 whilst those of the Kittiwake are dark 

 brown ; from the absence or very rudiment- 

 ary condition of the hind toe, this bird is 

 scientifically known as the Three-toed 

 Gull. The Black-headed, with deep coral- 

 red feet and legs, is perhaps the most 

 widely distributed of the species, and 

 therefore more deserves the title of 

 " Common " Gull ; moreover, its choco- 

 late-coloured head in summer is only 

 represented by a dark ear-patch in 



winter, at which season it straggles far 

 from the coastline seeking worms and 

 slugs and grubs Jrom flooded pastures 

 and freshly ploughed fields. On the 

 wing it shows more white than any of 

 the previous five. In all species the 

 young are more or less marked with 

 brown, and the tail feathers with black. 

 Immature birds of the three first-named 

 species are commonly mixed together as 

 " Grey Gulls." In flight the adult Com- 

 mon Gull shows white tips to the primary 

 flight feathers, whilst those of the Kitti- 

 wake are black throughout. A con- 

 spicuous white edge to the wdng distin- 

 guishes the Black-headed, and in the 

 hand the mouth and gape of the Common 

 Gull will be seen to be lead-coloured, 

 whilst that of the Kittiwake is vivid 

 orange. Maurice C. H. Bird. 



THE LIFE EPHEMERAL 



THE MAY FLY AND ITS LITTLE DAY 



By R. A. STAIG 



OF summer and the flowing stream are 

 the May Flies. Fragile creatures 

 — how softly they settle, folding 

 close their gauzy wings like a scintillating 

 sail ; their slender bodies curving elegantly 

 upward ; the long, dehcate tail filaments 

 waving to and fro. 



They cast their eggs upon the waters, 

 but the eggs are not swept away, for 

 each one has minute knobbed threads 

 which serve as anchors in the mud. Six 

 or seven months may pass ere the larvules 

 hatch out. Very slowly these tiny things 

 gffjw, gradually becoming large-eyed 

 lUTTiphs with sheathed wings showing 

 Ixliiiid the head, and with two or three 

 filiform tails, features suggestive of the 

 future flying form. And the rows of 

 little leaf -plates fringing their sides : these 

 are not oars for swimming, but appliances 

 for breathing, provided with air tubes, or 

 tracheae, by means of which the oxygen 



requisite for bodily aeration is extracted 

 from the water. 



Rounded in form and stout of limb 

 are the nymphs that burrow in the oozy 

 banks. The flat species are usually found 

 in swift streams upon the under surfaces 

 of submerged stones. They run rapidly 

 and with a wrigghng motion. Some 

 kinds, which have the tails thickly set 

 with cilia, swim freely. There are others 

 that wander about covered with mud 

 and are thus concealed. 



Two years, more or less, these larval 

 May Flies haunt the dark recesses of the 

 streams, then suddenly comes the hour 

 of their summer emergence to aerial hfe. 

 They float on the surface, the skin of the 

 back bursts open, and within ten seconds 

 out comes the winged Ephemera and flies 

 away. 



When the skylark soars in the zenith 

 of the heavens, carolling June-day vespers^ 



