Family and Generic Differentiation. 341 



but it has Robin-like habits, and the tj'pes of colour-pattern 

 of immature examples are so Robin-like that I think its 

 position might well be reconsidered*. 



Poecilodryas is another genus included with the Fly- 

 catchers, hut the young nestling of P. capito, with its very 

 curious colour-pattern and aberrant feathering, is not in the 

 least reminiscent of the young of this group. It recalls the 

 Huffy plumage on the back of the adult Corythociclda — 

 the Fluffy-backed Babblers. The yoiing of F. albifacies 

 presents the same peculiarities. The resemblance is so 

 striking that it seems to me we might well ask ourselves — 

 Is Picciludryas a Timeliine genus or a Flycatcher genus ? 



Again, it may be recalled that P. (jethiops, from New 

 Guinea, has always been included in the genus Pcecilodryas, 

 although it bore the most suggestive resemblance to Saxicola 

 caprata from India. Dr. Hartert has now removed it from 

 its former genus to the genus Saxicola. Is it possible that 

 in doing so he was in any way influenced, either consciously 

 or sub-consciously, by the factor of colour-pattern ? 



In the case of Pachycephala, a genus belonging to the 

 Laniidse or Shrikes, we have an instance of the colour- 

 pattern in the female giving a clue to true phylogenetic 

 relationship : for Pcecilodryas caniceps, which was formerly 

 regarded as a Flycatcher, we now find to be nothing more 

 than the female of Pachycephala gutturalis [P. obscurior 

 of Hartert). Was colour-pattern a negligible factor in 

 arriving at this conclusion ? 



I might add that the young of Pachycephala rujinucha 

 gamblei, from New Guinea, are well worth looking at from 

 the point of view of phylogenetic relationships. 



(8) The relationship of colour -pattern to the question of 

 genera-splitting or genera-lumping. 



In reality, the consideration of this aspect of colour- 

 pattern follows naturally on the heels of the last, and, in 

 effect, the few remarks which I shall have time to make 



* Since this paper was read 1113' attention has been drawn to the fact 

 that Mr. Oberholser had ah-eady noted the same point [cf. Proc. U.S. 

 Nat. Mus. 1915). 



