Correspondence 341 



bird to the list of enemies of tlie liouse fly (Musca domestica) and 

 the stable fly {8to»iojrys calcitrant), both members of a family 

 characterized by obscure markings and slight specific differences, 

 and which are much resembled by various flies of at least three 

 other families? Or would they list the yellow warbler as a predator 

 upon mosquitos, on the strength of field observations only, when 

 the number of species of small flies that superficially resemble 

 mosquitos is legion? If so, their idea of scientific accuracy is un- 

 usual. 



The writer in his original review tried to give a dispassionate 

 criticism of a single unfortunate tendency of papers by less ex- 

 perienced investigators. This was intended only as advice for fu- 

 ture caution and the general merit of the contributions was recog- 

 nized. The more of such intimate studies of birds, the better, 

 provided strict accuracy be kept in view. 



Professor Stephens, however, adopts a controversial attitude in 

 his rejoinder, which leads him to attribute to me sentiments that 

 exist only in his mental conception of me. His remarks also con- 

 tain unjustified conclusions resulting from ignorance, and innuendos, 

 which probably would not have been made had he adopted dispu- 

 tation rather than controversy as his medium. A few examples 

 follow : 



1. "The food of nestling birds, a field which seems to be guarded 

 zealously .... as the peculiar domain of the Biological Survey " 

 (]). 157). 



Nothing said in the review cited by Professor Stephens warrants 

 this insinuation, nor does anything that the writer has said else- 

 where. The Biological Survey has consistently encouraged and 

 assisted the scientific study of the food of birds, wherever attempted. 



2. Tlae proposal " to tie bags over the anal orifices of nestling 

 birds for the purpose of collecting the excreta will be highly amus- 

 ing to anyone who has noticed young birds in the nest" (p. 160). 



The proposal as stated may perhaps be amusing, but so far as I 

 know Professor Stephens is the only one who has made it. The 

 bags used by the writer have enveloped about three-quarters of the 

 whole bodies of nestlings, being tied on over the breast and under 

 the wings. All excrement voided was obtained, and the records 

 of different nestlings kept separate by the aid of different colored 

 tapes used on the bags. After a short time the parent birds did 

 not pay much attention to the bags. 



?>. "Vigorous, though quibbling criticism" (p. 160). 



No criticism can be called quibbling which definitely challenges 

 the accuracy of a scientific article. 



4. In two paragraphs, on page 160, Professor Stephens seeks to 

 les.'sen the effect of my statements that " a great many birds feed 



