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fi. Euchloe falloui obsolescens subsp. nov. 



1 t?, Ain Guettara ; 4 (?c?, 2 ? ?, north of Aiii Gnottani ; 2 (?(^, 1 ?, South 

 ned Mya. 



The distribution of E. falloui lias been given as from Algeria south of the 

 Atlas to Soinaliland, and the ? has been described by Riiber as a separate species, 

 E. seitzi. 



When in Ghardaia in April 1011 I was struck by some specimens taken by 

 Dr. Nissen which showed on the underside a great deal of yellow, and the trans- 

 verse green hands were more or less obliterated. I was going to describe this form 

 as a new subspecies when 1 received a male soraewiiat similarly coloured among a 

 batch of bred falloui from Victor Faroiilt. As he had mixed up the larvae bred 

 from El-Oiitaya and Bou-Saada parents, I determined not to describe it till I could 

 get authentic material. Meanwhile, in discussing matters with Dr. Nissen (the 

 Danisli Oonsul-CJencral at Algiers), it suddenly struck me that this form with 

 obsolescent bauds might be the summer brood oi falloui, just as glauce is of 

 helemia. This has since been confirmed by the receipt by Dr. Nissen from 

 (ihardaia of spec'imens of falloui taken in March of this year, which are much 

 more strongly banded liolow, and dcj not show any yellow. This, however, by 

 uo means ends tlie matter. Dr. Martert obtained the above ten examples in a 

 jjortion of the Sahara where no zoological collections have ever been made, and 

 the males show even greater reduction of the liands than those from Ghardaia. 

 Although I was still convinced that we had only a case of second generation. 

 Dr. Hartert was so insistent that there appeared to be other differences, that I 

 have carefully compared Biskra specimens with Ghardaia ones and the above ten 

 specimens, and I have come to the conclusion that the form found at Ghardaia 

 and farther south is separable from those which fly oa the edge of the desert and 

 reach into the region of the " Hants I'lateaux.'" 



This form, for which I propose the name oi falloui obsolescens, differs from 

 /. falloui in the spring generation in very few points ; in fact, I think the only 

 real dilferciice is that the green bands are more clearly separated, more definite 

 in outline. The summer generation, however, is startlingly ditl'erent ; in the 

 more northern form the green bands are in the majority of individuals strongly 

 tinged with yellow and rather more coalescent, the outlines being irregularly 

 expanded after the miinner of the summer generations of auso/iia and bdcmia ; in 

 the southern form these green stripes become almost obliterated, and of a 

 gallstone-yellow colour. Althougli 1 have handled and examined more than a 

 hundred specimens of the summer form from the north, 1 have only seen two 

 specimens similar to Ghardaia ones, and none as extreme as those from the 

 Oued Mya, which are as pale below as extreme specimens of P. J. nlbidice. 



Type, S. South Oued Mya, 10. iv. 1012. 



[We took great jiains to get a series of this form oi falloui, but only succeeded 

 in ■■■etting these ten specimens. They were very much rarer than Pieris dnplidice 

 nlhiiliri', though flying in the same ]>laces in the southernmost part. A single female 

 was caught a kilometre south of the gorge of Ain (inetfara, in tlie morning at half- 

 past five ! 



It is strange to me, in view of the well-known variability of Pieridae, how 

 ^^ EiichloiJ seitJ:i" could be desi^rihed as a new species from two specimens, from the 

 typical locality oi falloui I — E. H.] 



