Vol.X 

 1S93 



Correspondence. S7^ 



which in masses produce a definite color pattern. Mr. Allen's little excla- 

 mation about "the fewer facts for a nicel}' spun theory the better" is conse- 

 quently not inserted in a suitable place, since I am not dealing with 

 theories in this particular instance. 



While Mr. Allen's objection that the pigment is deposited before the 

 feather leaves the sheath does not interfere with my view of deposition 

 along lines of greatest and least resistance, it may very seriously interfere 

 with his own theory of climatic influences o.n color (which I have also 

 accepted in my paper). Mr. Wallace writes me as follows on this subject : 

 "There is a point you do not refer to which seems to me most important — 

 that is, whether the colours and markings of the feathers are developed 

 in the young feather before it has opened out of its sheath, as we know 

 that all the markings of the wings of butterflies are to be seen before it 

 emerges from the pupa. If it is so, then climate can hardly have any 

 direct influence."^ It is quite apparent that if Mr. Allen is not prepared to 

 admit that some pigment is either deposited on or withdrawn from the 

 fully formed feather, then climate can produce no effect on pigmental 

 colors. It would thus seem as if he should at least be willing to share the 

 humiliating mistake with which he charges me. [4] 



In a foot-note he also alludes to a supposed new feather structure noted 

 by me in 'Zoe,' and refers me to Coues's 'Key to North American Birds' 

 for a description (p. S6). Following is the description there given : 

 "Filoplumes, jilopliinur, or thread-feathers, have an extremely slender, 

 almost invisible stem, not well distinguished into barrel and shaft, and 

 usually no vane, unless a terminal tuft of barbs may be held for suck." 

 Upon referring to Nitzsch I found only two forms of filoplumes figured, 

 both with the terminal tuft of barbs, and I consequently supposed the 

 structure which I briefly and tentatively recorded as having no barbs 

 whatever, was different. Upon further examination of the text of Nitzsch 

 I find he has included this form also under the head of filopluma, without, 

 however, figuring it in the plate. 



Mr. Allen is also quite right in saying that I have been handicapped in 

 my work by insufficient knowledge of exotic birds, my opportunities for 

 studying these having been very limited upon the Pacific Coast where no 

 satisfactory collections are available. In speaking of patterns of marking 

 with which I am unfamiliar, I had no intention of asserting that such 

 did not exist, but simply that they were quite unusual if they did occur 

 among North American species, whereas other forms are very often 

 repeated. Exceptions (even a considerable number of them in fact) would 

 not invalidate the conclusions so long as a fair ratio was maintained 

 between the unusual forms and the most common styles. 



Mr. Allen must have taken especial pains to discover a contradiction 

 where none exists in referring to the Brown Creeper, in order to bring in 

 his phrase of "slipshod generalization." [5] It would seem as if in a paper 



1 Italics mine. 



