Stomach-contents of Birds. 639 



brought up in the course of a single day; so that, even were 

 all chitin held over for evacuation by mouth, the examiner 

 of a bird's stomach could expect to find there at a given 

 moment indications of the food eaten during only a 

 comparatively short time previously. Even the most minute 

 examination of a merely moderate number of stomachs of a 

 given species cannot, therefore, be held to have necessarily 

 thrown full light on its feeding habits. 



I need not, I think, enter into the question, " Why have 

 more actual attacks on butterflies not been witqessed "? In 

 the first place, it is outside the scope of this note ; in the 

 second, Mr. G. A. K. Marshall's splendid collection of records 

 (Trans. Ent. Soc. 1909, p. 329) tends to shew that many 

 more have been witnessed, and recorded than seems to have 

 been commonly supposed ; and, thirdly, Dr. Trimen's 

 suggestion (Proc. Ent. Soc. 1897, p. 89), *^ the neglect of 

 well-directed and sustained observation," doubtless accounts 

 for much. But (for reasons already stated under No. 5 

 above), I should, in any case, so far as Chirinda is con- 

 cerned, be extremely surprised to see as many or, under 

 ordinary circumstances, anything like as many attacks on 

 butterflies as on insects of other Orders. 



To sura up the actual subject of this note, my recent 

 work has convinced me that conclusions based on stomach- 

 examination are likely to be fallacious, unless that 

 examination has been so thorough and minute that even 

 such small objects as the scales of Lepidoptera must have 

 been detected if present even in small numbers, in either 

 stomach or intestines, unless a very large series has been so 

 examined for each sj)ecies, and unless, finally, a note had been 

 made at the time of the shooting of each specimen as to 

 the probable proportions in which insects of various Iduds 

 were present at the moment. The re-examination is also 

 suggested of all such stomach-contents, still available, as 

 have not been already thus exhaustively investigated, special 

 attention being paid to the dust and finer debris. The 

 difficulty of distinguishing between moth and butterfly debris 

 will always be present, yet even here something may perhaps 



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