( t2 ) 



.C^ONOLUSIONS. 

 I. 



The iiumlier of species diminishes from the foot of tlie Atlas southwanls. 

 Some of tlio birds which oiiliveii the northern S.iliara, as for exaini>le near Biskra 

 and even Ghardaia, especially the Crested Larks, Ilhami>hororijH, KremO))Iiila, 

 Oenanthe {Saxicola) moetsta, Calaiidrclla minor, LaniiiH excuhitor filegans, Art/i/a 

 /ulca, Caccabis and others— disappear entirely, mostly between El-Golea and 

 Ghardaia on the one, and El-Golea and Tonjrgonrt on the other side. 



Some of the species, such as En/throspizn (jitluKjinea, Athene, and others, 

 though extending far southwards, become very local and very scarce. 



II. 



A few of the species are represented by different subspecies in the central and 

 in the northern Sahara : Corcus corax tingitamis by C. c. nifieollis, Ammomanes 

 desert i algcriensis by .1. d. mija. 



III. 



Some of tlie birds, and still more so the lepidoptera, coleoptera, mammalia, 

 and plants, arc very widely distribnted, especially many insects and plants range 

 at least from Arabia and Syria to Marocco, and from Spain to the central 

 Sahara. This is no doubt due to the similarity of desert-country and desert-climate 

 in the various countries and the unbroken desert belt extending from Syria and 

 Arabia to the Atlantic Ocean. 



IV. 



The breeding season varies more than in Europe. I do not agree with Coant 

 Zedlitz, who concludes that Passer simplex saharae breeds twice in one year ; 

 but, since we found fully fledged and naked tiny yonng birds as well as nearly fresh 

 eggs almost at the same time, I mnst believe that this bird breeds more irregularly 

 than most birds in our country. The same is to be said about Oenanthe leucopyga 

 aegra, Alaemon, and others. 



I am, of course, well aware of Count Zedlitz' most interesting articles in 

 Journ.f. Orn. 1908 p. 480 and Verh. V. fntern. Oni.-Kongr. p. 323. I have also 

 experienced myself the great influence of rain in the Sahara. In 1908 and 1909 

 Mr. Rothschild and I, at various times from February to the end of April, 

 collected in the stretch of country between Biskra and Bordj Saada, and in 1909 

 we rode from Biskra to Touggourt and back. Very seldom did we see a single 

 white butterfly between Biskra and Bordj Saada, and not one all the way from that 

 Bordj down to Tonggonrt. In 1912 I saw dozens of white butterflies between 

 Biskra and Bordj Saada, and hundreds of Melitaea and yellow-and-white Euchloe 

 between Biskra and Touggourt — evidently because there had been more rain in the 

 winter and any amount of vegetation. Whether this could affect the breeding-time of 

 a Passer simplex saharae I cannot say, but I doubt it very much. To seek an 

 undoubted explanation one would have to remain longer in the central Sahara, 

 or visit it more often, and in years with and without considerable winter rains. 



