62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



to the vast body of speculation that has proceeded from slight premises 

 by data in a preceding paragraph apparently indicating that birds do 

 not eat many chrysalides of butterflies. For in that case we must refer 

 him to Bryant's statement that about 15 per cent of the pupae of 

 Eugonia calif ornica at a time when they were very abundant showed 

 evidences of attack by birds (Condor, vol. 13, p. 200, Nov., 1911), 

 and to Chittenden's that " in one case it was found that during the 

 winter the number of pupae of the cabbage butterflies was reduced 

 more than 90 per cent by birds feeding upon them." (Farmers' 

 Bull. 766, U. S. Dep. Agr., p. 9, 1916.) 



In this paper w^e cannot possibly discuss all of the data relating to 

 predators upon insects and other animals, but the evidence we present 

 in our tabulations surely goes far to prove that no groups are neglected 

 by predators (except as availability or sheer size dictates) and that 

 the various groups are preyed upon more or less in proportion to their 

 numbers. As applied to Lepidoptera this rule is apparent in the 

 greater number of records for such large families as the Noctuidae, 

 Tineidae, and Tortricidae for instance as contrasted to such smaller 

 ones as the Sphingidae, Arctiidae, and Bombycidae or of the more 

 numerous Nymphalidae to the less numerous Papilionidae. Due to 

 the high proportion of unidentified Lepidoptera, our tables are not as 

 complete and informing as could be desired, but where there are ap- 

 parent exceptions to the rule of proportional loss to predators, data 

 from other sources usually indicates unreliability of the apparently 

 negative evidence. For instance the records of Geometridae in our 

 table seem too low for this rather important family which is un- 

 doubtedly numerous in individuals. But that this is due solely to the 

 make-up of our material is proved at once by reference to the litera- 

 ture ; no fewer than y^ species of nearctic birds have been observed 

 feeding on cankerworms (Paleacrifa and Alsophila) for instance. 

 Wellhouse, who reports finding cankerworms in 98 of 100 stomachs 

 of birds (36 species) collected near Lawrence, Kans., in 34 of which 

 they composed the total food, says : " Probably no insect is a favorite 

 food of more species of birds than the cankerworm larva." (Bull. 

 Univ. Kansas, vol. 18, no. i, p. 301, Oct. 1917.) In a study of birds 

 in relation to cankerworms in Illinois, Forbes found these larvae to 

 compose 45 per cent of the food of a collection of 55 birds (15 species) 

 and that one species, the cedarbird, was destroying them at the rate 

 of at least 90,000 per month. (Forbes, S. A., Trans. Illinois State 

 Hort. Soc. (1881), pp. 123-130. 1882.) 



