634 Otto Herman : 



(8) Hirundo rustica L. feeds on flying insects which are 

 mostly indifferent. 



(9) Muscicapa grisola L. destroys many noxious insects ; it 

 does not, however, spare the honey-bee and eats even the 

 spanish-fly. 



(10) Muscicapa atricapilla L. Besides many noxious in- 

 sects, we find in its stomach honeybees also. 



(11) Muscicapa collaris Bechst. Same as above. 



(12) Guculus canorus L. destroys many noxious insects, 

 chiefly caterpillars and May-beetles. 



(13) Cerchneis vespertinus (L.) destroys an immense number 

 of insects, rarely small Vertebrates. If it devours here and 

 there a bird, it is still useful in regard to agriculture. 



(14) Cerchneis tinnunculus (L.) is useful, its food consisting 

 of insects and mice. 



(15) Dendrocopus major (L.) is useful. 



(16) Dendrocopus médius (L.) is useful, though it chiefly 

 eats indifferent insects. 



(17) Dendrocopus minor (L.) is indifferent. 



(18) Dendrocopus leuconotus (Bechst.) is useful. 



(19) Picoides tridactylus (L.) is useful. 



(20) Picus viridis L. is indifferent, its food consists of 

 multitudes of ants belonging to indifferent species. 



(21) Picus canus (Gm.) is indifferent. 



(22) Dryoscopus martius (L.) is useful, its food consists of 

 larvse of wood-destroyers and wood-ants. 



(23) Jynx tor quitta L. is rather indifferent than useful, 

 its food consists of indifferent ants ; other and noxious 

 insects are rarely found in its stomach. 



(24) Upupa epops, L. is useful, destroys many noxious 

 insects and their larvœ. 



(25) Gaprimulgus europaeus, L. is useful and destroys many 

 noxious insects and their larvae, e.g., May-beetles. 



(26) Coracias garrulus, L. is useful, though the contents 

 of its stomach are sometimes found to be composed of useful 

 insects also. 



The results of these investigations were published in 

 Yol. XI. of Aquila. 



On account of the divergence of opinions, a special study 

 was made of the Rook (Gorvus frugilegus L.) 



