THE BUTTERFLIES OF LOWER EGYPT. 61 



published by Mr. P. P. Graves in the Entomoloiiist'n Uecord, 1904, and 

 these notes may be regarded as supplementary to that paper. Mr. 

 Graves is in Cairo at the time of writing, having had an exciting and 

 trying time in getting out of Constantinople at the declaration of war. 

 We hope to forget our labours for the moment in a jaunt into the 

 desert for the few but interesting insects that occur there. Egypt is 

 sufficiently well known to make any remarks on the country super- 

 fluous ; but one scarcely realises, until one actually sees it, the extra- 

 ordinary proximity of the most fertile land probably in the globe with 

 the most sterile ; the dividing line is most strongly drawn, a yard even 

 separating the two ; the cause, of course, being the fertile alluvium 

 brought down by the annual Nile flood. This makes it difficult to 

 say, in many cases, what are actually desert species and what not, 

 particularly among the Hymenoptera, as, owing to their powers of 

 Sight, they spread from cultivated districts far into the desert, being 

 attracted at certain seasons of the year by the flora that grows in the 

 bottom of the valleys, which meander far into the hills and which 

 debouch on to the desert plains in close proximity to the Nile's over- 

 flow. Dragonflies also are extraordinarily wandering creatures ; though 

 found usually in the neighbourhood of water, they occur miles from it 

 in the very heart of the desert, and some butterflies whose larvae feed 

 on garden plants, by means I do not attempt to explain, have thrown 

 o&' their usual habits and have become entirely denizens of the desert. 

 I'ontia dajilidice is one of these ; on the continent of Europe, so far 

 as I have observed it, this may be regarded almost as a garden insect, 

 but I was surprised to find that the only locality, except for an 

 occasional stray specimen, was the desert ravines miles away from 

 cultivation of any kind. In Egypt it is a scarce insect, and the only 

 two specimens I have taken were a pair at Wadi Hof, on March 8th, 

 1914. They were flying about some dried-up grass at the bottom of 

 the ravine, which, even at this early period of the year, was very hot, 

 and the vegetation already becoming desiccated with the heat. 



A)ith(jcharis belia, a butterfly I have not yet met with here, is also 

 an entirely desert species. 



The appearance of butterflies in Egypt, more especially those of 

 the desert, is very largely dependent on the rains which usually fall in 

 the winter months. These are very capricious, occasionally, perhaps 

 once in fifteen or twenty years, there is such a heavy downfall, that 

 the Wadis become raging torrents, banks and roads are washed away, 

 and considerable damage is done to property. 



On the other hand, no rain or a few drops only may fall for two 

 or three years, and the average at Cairo is but a little more than an 

 inch. 



Last year, 1913-1914, the rains almost entirely failed and con- 

 sequently the desert plants, which are entirely dependent on them for 

 their spring and early summer growth, scarcely flowered at all and put 

 forth a very scanty leaf, the result being that all through the year the 

 desert flora was by no means in evidence. Butterflies are likewise 

 affected by the climate. In what stage the desert butterflies pass the 

 hot dry summer months I am unable to say, it probably varies with 

 the species, but there is little doubt that if the winter rains fail the 

 species emerge in verj' diminished numbers, and it is quite possible 

 that under these circumstances the earlier stages take more than a 



