2 1 A. Von Ihering, Biology of the Tyrannidce. Ljuly 



' Revista do Museu Paulista,' is purse-shaped and suspended at 

 the extremity of a branch. It has a round opening in the middle 

 protected by a shelter above, I have quite similar nests of Todi- 

 rostriim cinereum, Orchilus auriai/aris, Hemitriccus diops, and of 

 different species of Euscarthmus. The same form of nest is, 

 therefore, common to the genera Flafyrhynchiis, Todirostrufn, Eus- 

 carthmus and Orchilus. Moreover, the eggs of the members of all 

 these genera are yellowish white or brownish with very fine points 

 on the larger end. 



On the other hand the nests of Serphophaga are placed among 

 the diverging boughs of a branch and are cup-shaped, while the 

 eggs are of a uniform yellowish white. Of the same type are the 

 nests and eggs of Aticereies and Hapalocercus. The nest of 

 Phylloscartes ventralis, however, as Mr. Krone assured me, has 

 one wall of the nest elongated above and recurved, forming a 

 somewhat globular, domed structure. 



A form of nest like that of Serphophaga is found in the genera 

 Elainea and Phyllomyias, and in other Elaineinae, among which, 

 however, occurs also a second form of nest. This form is illus- 

 trated by the nest of Ornithion obsoletum which I have recently 

 examined. It is of a pear-shaped form, similar to that of Euscarth- 

 mus, but not suspended from the top of a twig but fixed at differ- 

 ent points on the branches. 



Euler has described the nest of this species differently, but the 

 nest observed by him, which was much hidden between masses of 

 Tillandsia, was not probably of a normal form. Besides, O. obso- 

 letum does not occur in Rio de Janeiro and Bahia, where the spe- 

 cies is represented by O. cinerasce?is (Wied), which, in opposition 

 to Mr. Allen, I do not doubt is identical with O. imberbe Scl. A 

 similar nest is built by Mionectes rufiventris (Licht.), as has been 

 observed by Mr. Krone. 



The nest of Ornithion forms the transition between that of 

 Serphophaga and that of Euscarthmus. We may be justified to 

 assume that such an artificial and wonderful construction as the 

 nest of Euscarthmus is not the work of free invention but is to be 

 considered as the result of development from a previous form of 

 nest. We have but to suppose the nest of Ornithion, instead of 

 being fixed on various branches successively, to be placed on one 



