1885.] MR. p. L. SCLATER ON A NEW ICTERUS. 671 



specific separation of the ' Seefrosch,' and the small race of the green 

 aquatic frog, or the blue and green varieties of the same, and the 

 importance of the above result is increased by the fact that the 

 spawning-seasons of the crossed races do not coincide." 



The difiPerence in the spawning-season is the important factor 

 which permits the existence in the same locality of two forms so 

 closely allied and yet so distinct, as no doubt occasions for inter- 

 breeding must be extremely rare. Analogous instances are known 

 in Botany, as my friend Prof. Errera kindly informs me, and the 

 name ' Asyngamie ' has been coined for them \ It is indeed a fact 

 that a fortnight's interval in the breeding-time of the two races must 

 constitute a very effectual obstacle. As far as my experience goes, 

 the females get rid of their eggs within a very few days. Having 

 received this spring, through the kindness of Dr. F. Miiller, about 

 25 specimens of R. esculenta from Basle, all the females laid 

 their eggs in the nights of May 29-30 and 30-31, save one which 

 spawned two days later. When, on the 27th of May, 1884, I 

 received from Koack 85 specimens of R. ridibunda and 41 oi R. escu- 

 lenta, I found that all the females of the former kind had done 

 spawning, and the males gave no signs of breeding dispositions ; 

 whereas all the R. escidenta 1 opened were full of ova, and out of 

 the few males I possessed, two actually seized hold of females of 

 their kind. But I did not obtain any spawn. 



4. Description of a new Species oi Icterus. By P. L. Sclater, 

 M.A., Ph.D., F.R.S., Secretary to the Society. 

 [Eeeeived June 11, 1885.] 



"While engaged in the determination of the specimens of Icteridse 

 in the British Museum of Natural History, I have found amongst 

 them a single skin of a typical Icterus, formerly in Mr. Gould's 

 collection, which appears to belong to an unrecognized species. I 

 propose to name it after the well-known collector so long resident 

 on the Upper Amazons, by whom it was originally procured. 



Icterus hauxwelli, sp. nov. 



Flavissimus, aurantiaco tinctus : loris et capitis lateribus, cum 

 (jvtture toto usque ad medium pectus, intcrscapulio angusto, alls 

 et Cauda nifferrimis : alis jnacula in secondariis alba ornatis : 

 subalaribus Jlavis : rostro et pedibus nigris. Long, tola 8*j, 

 ola 3"75, caudce 3"7. 



Hab. Amazonia Superior ; Chamicuros (Hauxiuell). 



Mus. Brit. 



Obs. Species macula alari alba I. grace-annce proxima, sed cauda 

 tota nigra sane diversa. 



^ Cf. A. Kerner, Vorlaiifige Mittheiluug iiber die Bedetuung der Asyngamie 

 fiir die Entstehung neuer Arteii : Iiiusbruck, 1874. This paper is mifortunately 

 only known to me through the abstract in the Botan. Jahresber. for 1874, 

 p. 903. 



