September 1, 1905.] 



SCIENCE. 



275 



and Michigan. However, the birds are most 

 common about the lower reaches of the Con- 

 necticut and Hudson rivers. At the present 

 writing I have no doubt that in all the col- 

 lections in the country there are at least 150 

 individuals of H. leucohronchialis and, more- 

 over, it is entirely possible, at the proper 

 season and locality, to observe these birds 

 annually. 



Again I must insist upon the importance 

 of considering carefully the history of the 

 appearance of this and other probable ' muta- 

 tions.' It is not likely that a form or kind 

 of bird so common as H. leucohronchialis is 

 at the present time, and ranging over as large 

 an area as from Pennsylvania to Massachu- 

 setts and from Virginia to Michigan, should 

 remain unknown to the earlier ornithologists, 

 such keen field naturalists as Audubon and 

 Wilson, Baird, Lawrence, Coues and Prentiss. 

 Nuttall made careful and prolonged study of 

 birds in the region where Mr. Brewster col- 

 lected the type. Yet none of these close ob- 

 servers and good collectors either recorded or 

 secured an individual of this kind. Clearly 

 then, the presumption is that this bird could 

 not have been so coramon early in the last 

 century as it is now, if indeed it existed at 

 all at that time. Nor does it seem that the 

 theory of hybridity° is supported when we 



" ' On the Relationship of Helminthophaga leu- 

 coh7-onchialis, Brewster, and Helminthophaga 

 lawrencei, Herrick; with some Conjectures Re- 

 specting Certain other North American Birds,' 

 by William Brewster, Bull. Nutt. Orn. Chib, Vol. 

 VI., No. 4, pp. 218-225, 1881. Basing his hy- 

 pothesis upon similarity of color and marking, 

 Brewster considers these birds hybrids and says : 

 ■'Taken as a whole, this series (of seven speci- 

 mens) perfectly connects leucohronchialis with 

 pirMs, as well as showing an extension of the 

 former towards chrysoptera.' 



' Helminth ophila leucohronchialis,' by Robert 

 Ridgway, Auk, Vol. II., No. 4, pp. 359-363, 1885. 

 Assumes Helminthophila leucohronchialis to be 

 a distinct species which hybridizes with its allies, 

 thus accounting for the number of aberrant speci- 

 mens. 



'Helminthophila leucohronchialis in New 

 Jersey,' by E. Carlton Thtirber, Morristown, N. J., 

 Auk, Vol. III., No. 3, p. 411, 1886. Records the 



ecnsider the vast number of known specimens 

 already in collections and the fact that it is 

 possible to observe living specimens, as I have 

 indicated, each year. I am aware that many 



capture by Mr. Auguste Blanchet of a specimen 

 aboiit ten miles from Morristown, in May, 1859. 

 He says : ' The whole plumage resembles somewhat 

 that of the female H. chysoptera, but the grayish 

 on the breast is not so deep.' Mr. Thurber regards 

 this bird as a hybrid. 



' An Interesting Specimen of Helminthophila,' 

 by William Brewster, Cambridge, Mass., Auk, Vol. 

 III., No. 3, pp. 411-^12, 1886. Records another 

 specimen taken by Mr. Frank Blanchet two miles 

 from Morristown, N. J., on May 15, 1884. The 

 sex was not determined. Mr. Brewster writes of 

 this specimen that it ' * * * is apparently a 

 hybrid between the hybrid H. lawrencei and the 

 typical H. pinus.' After describing the bird with 

 much detail he adds : " In briefer terms, this 

 interesting bird may be said to be about inter- 

 mediate in color and markings between typical 

 pinus, with its short narrow eye-stripe and uni- 

 formly yellow underparts, and the so-called H. 

 lawrencei, which has a broad black patch ex- 

 tending from the bill through and beyond the eye, 

 and the chin, throat and forepart of the breast 

 solidly black. It forms an important link in the 

 chain of evidence supporting my theory (Bull. 

 Nutt. Orn. Cluh, Vol. VI., No. 4, pp. 218-225, 

 1881) that H. pinus and H. chrysoptera fre- 

 quently interbreed, and that their offspring per- 

 petuate a variously characterized hybrid stock 

 by breeding back into one or the other parent 

 strains." 



' The Significance of Certain Phases in the Genus 

 Helminthophila,' by Spencer Trotter, M.D., Auk, 

 Vol. IV., No. 4, pp. 307-310, 1887. Accepting the 

 theory of hybridity. Dr. Trotter believes, because 

 of its apparent common occurrence, as represented 

 in the many specimens of H. leucohronchialis, 

 that it indicates the degeneracy of the species 

 producing this hybrid. He concludes, therefore, 

 that the extinction of chrysoptera and pinus is in 

 process, and perhaps imminent. 



' Notes on Birds Observed in the Vicinity of 

 Englewood, New Jersey,' by Frank M. Chapman, 

 Auk, Vol. VI., No. 4, pp. 302-305, 1889. Mr. Chap- 

 man writes of leucohronchialis as ' this puzzling 

 hybrid.' 



Cf . Ridgway, ' Manual of North American 

 Birds,' 1896, footnotes on page 486. Mr. Ridg- 

 way advances the dichroic theory plus hybridity 

 to account for lawrencei and leucohronchialis. 



