NO. 7 PROTECTIVE ADAPTATIONS McATEE 69 



beetles (18,548 nearctic species) fully satisfies expectations based on 

 the relative availal)ility of the species to birds. 



Species of Agonodenis, much more common than Lebia but just as 

 contrastingly colored, contribute 188 records to our tabulations and 

 were eaten by no fewer than ^y species of birds. From 10 to as many 

 as 50 specimens had in several instances been taken at a meal. There 

 are 57 records for Casnoiiia, a small genus of " long-necked " dis- 

 tinctly " warningly-colored " beetles in stomachs of 14 species of birds. 



Even black, alone, the predominant color among Carabidae has been 

 held to have a warning value, but Aniara. Anisodactylus, Harpalus. 

 and Plerosticluis, chiefly typically black species, are eaten by the 

 hundreds. There are 445 records for the powerful Pasimachus (80 

 individuals in one crow stomach), and 497 for the species of Colosoma 

 which are not only large, but some of which have contrasting blue 

 margins, others fiery spots, and all powerful, ill-scented excretions. 

 In fact, it is everywhere evident that the special defenses alleged for 

 the Carabidae are more in the nature of pleasing fictions for theorists 

 to speculate upon than practical reliances for the beetles concerned. 

 Eloquent is the fact that between a sixth and a fifth of all determina- 

 tions of beetles in the stomachs of nearctic birds are of Carabidae. 



The Haliplidae, all of which have " warning colors," and the 

 Dytiscidae and Gyrinidae, said to be protected by anal glands, all seem 

 to be preyed upon in proportion to their abundance. The Silphidae 

 quite generally have nauseous excretions and include numerous species 

 with distinct warning colors, but it is the latter forms such as Necro- 

 phonis with 102 records and Silplia with 213 that most evidently are 

 eaten in due proportion. The apparent falling of records of this 

 family below the index of frecjuency must be attributed to the smaller 

 and rarer species with more concealed habits being overlooked, rather 

 than to the larger familiar ones enjoying immunity on account of 

 alleged special defenses which they possess in the highest degree. 



That the Staphylinidae is the family most numerous in species, and 

 probably therefore of individuals, among all Coleoptera is a fact not 

 realized by the average collector. It has been brought out only by the 

 accumulated research of generations of coleopterists, and its lack of 

 obviousness must be attributed to the secretive habits of so many of 

 these small or even minute beetles. Most of them spend their lives 

 chiefly under cover of various kinds, for example, in fungi, in leaf- 

 mold, under bark, in old logs, and in ant nests, and it must be on this 

 account that the records of birds capturing them are not very much 

 more numerous, rather than that they are disliked. In fact the 1,605 

 determinations for them proves they are not disliked, and these 



