No. 2.] PROTECTIVE RESEMBLANCES IN SPIDERS. 63 



The humming-birds feed largely on our small spiders. 

 Mr. Gentry tells me that he has opened hundreds of stomachs 

 of the Eubythroat (Troch. colubris), subjecting them to micro- 

 scopical examination, and has always found an abundance of 

 small spiders associated with Coleoptera and Aphidse, the spiders 

 being ten times more numerous than the other insects. This 

 agrees with the statement of Mr. Belt that he has found the 

 crops of humming-birds full of small, soft-bodied spiders.* 



In Central and South America the destruction of spiders 

 from this source must be enormous, since in those countries the 

 humming-birds are exceedingly numerous. Mr. Belt estimates 

 that they are so plentiful in some parts of Nicaragua as to equal, 

 if not to greatly exceed, all the other birds together.! 



In both temperate and tropical regions a dreaded foe of 

 spiders is the solitary wasp. This strange creature stings and 

 lays up as food for its larvae great stores of spiders, or in some 

 species, beetles, flies, or caterpillars. 



Reports from many parts of the world show how universal 

 is the enmity between spiders and wasps. Fabre, in speaking 

 of some European species of Pompilidse and of the spiders with 

 which, they do battle, says : " D'une part sont les Pompiles, 



Bluebird. 8%; House-wren. 6% ; Chestnut-sided Warbler, 6 '!-o; Summer Yellow-bird, 

 6% ; Yellow- winged sparrow, 30%. 



Mr. Thomas Gentry has, with a kindness which I gratefully aclsnowledge, made 

 out for me the percentage of spiders in the food of the land birds of Eastern Pennsyl- 

 vania. It will be seen that his results agree with those of King and Forbes in show- 

 ing that the Arachnidainrnish but an insignificant part of the food of North American 

 birds, always excepting the TrocMlidm. 



The Turdidcr, consume a few spiders, but the ratio to the whole number of 

 insects eaten is so small as to be of little value. 



Saxicolidm, about 2%; Sylviidsi, less than ii% ; Paridte., less than ^i%; Sittidce 

 1%; CertMidcE,M%\ Troglodyiidce,2%; Sylvicolidce,2%; Tanagrid(e,%%; Hirundi- 

 nidx, 1%\ Ampelidas, none; Vireonids:, 2%; Laniidx, none; Fringillidx, repre- 

 sented by 28 species, .01%%; 0. passerinus consumes about 32%; P. gramineus, often 

 as much as 10%. 



Icteridie, represented by eight species, are occasional spider eaters, especially 

 the sub-family Jcffin'n^. Gorvidx, none; Tyrannidse, ^i%; Caprimulgidx^ occasional 

 traces of .spiders: Oyprelidx, very few; TrochUidx, 80%; Alcedinidm^ none; Cu- 

 CMHdK, a few traces ; Picidx,i}^?4; Strigida;, none; Falconidx, none; Cathartidie, 

 none; Cohimbidx, none; Tetraonidx, none. 

 * The Naturalist in Nicaragua, p. 315. 

 I Loc. cif., p. 140. 



