244 Correspondence. [ April 



that in my account of the pteryloses of the swifts and hummingbirds, I 

 made use only of "Nitzsch's figures, which are, unfortunately very inac- 

 curate" (p. 69), and, further, that the "position" I assume "is clearly 

 based on insufficient or unreliable evidence." Both of these statements 

 or insinuations are utterly without foundation. In common with most 

 writers on pterylography, I make constant reference to Nitzsch's figures, 

 but in nearly every instance in a critical way, pointing out his deficient 

 comparisons, oversights, and lack of elaboration of the subject. In so 

 far as the swifts and hummingbirds go, I had ten times, or more, the amount 

 of material before me, illustrating those two groups, that Nitzsch had when 

 he wrote his 'Pterylographie,' and I hardly think that any one will ever 

 charge me with not having used "the evidence." A partial list of my 

 material is presented in my Linnsean article, and I have examined scores 

 of other specimens not enumerated there. That list includes a varying 

 number of individuals of two species of trogons; three genera of the Cap- 

 rimulgida?; various swifts, and a great many hummingbirds; and, finally, 

 all the forms of our swallows known at the time, and two species of Ampelis 

 for comparison. So far as the hummingbirds and swifts are concerned I 

 place more reliance upon what is to be found in the cases of freshly killed 

 specimens, than I do upon many alcoholics, for the reason that it too often 

 happens in the case of the latter, that they are specimens left over that the 

 field collector did not have the time to skin, and in a day or two throws 

 them into alcohol. Now with the tropical hummingbirds and many other 

 forms, this means that the early stages of dermal decomposition has set in 

 and the feathers on the gular area, the abdomen, and elsewhere will come 

 out and be lost. This I have had happen in the case of some swifts I col- 

 lected in New Mexico, and often in the hummingbirds. 



When he comes to discuss the feather tracts of the Cypseli (p. 70), Pro- 

 fessor Clark states that " On the anterior part of the neck, close to the head, 

 is a large and very evident apterium, one of the most characteristic features 

 of the pterylosis." He states that I "positively" deny "the existence of 

 this apterium in the swifts," and I would like to ask my critic where I 

 make any such denial. The locality referred to, being on the anterior 

 part of the neck in a short-necked bird like a swift can be nothing less than 

 the gula (or the gular area or region) , and I fail to find any special reference 

 to it in my writings anywhere. What I did deny was the presence of the 

 nuchal apterium in the swifts and swallows, but recognized its presence in 

 the hummingbirds. It is certainly absent in the swallows, and personally 

 I have never met with it in the case of a swift; but then I have only ex- 

 amined some forty or fifty of them for the purpose (Chatura, Cypseloides, 

 Cypselus, and Aeronautes). 



Professor Clark further states that I deny the presence of the "supra- 

 ocular apteria " in the swifts (p. 90), whereas I do nothing of the kind, 

 but simply invite attention to the fact that Nitzsch figures them for Cyp- 

 selus, and as I did not dispute his recognition of their existence, it is fair 

 to presume that I recognized the presence of those apteria in the Cypseli 

 generally. The fact of the matter is, twenty years ago I believed that . 



