374 



Annals Entomological Society of America [Vol. XII, 



Phormia metallica Townsend^ and Hylemyia nidicola Aldrich. 

 The frequency with which the larvae of Phormia azurea Fallen 

 were encountered in birds' nests, and the number of larvae and 

 pupae per nest, is shown by the following tables: 



TABLE I. 



Species of Bird 



Nuttall Sparrow {Zonotrichia leuco- 

 phrys nuttalli Ridgway) 



Rusty Song Sparrow {Melospiza 

 melodia morphna Oberholser) 



Willow Goldfinch {Astragaliniis tris- 

 tis salicamans (Grinnell) 



Oregon Towhee {Pipilo macula tus 

 oregonus Bell) 



Russet-backed Thrush {Hylocichla us- 

 tulata (Nuttall) ' 



Western Robin {Merula migratoria 

 propinqua (Ridgway) 



Cedar Waxwing {Ampelis cedrorum 

 (Vieillot) 



Yellow Warbler (Dendroica aestiva 

 (Gmelin) 



Cliff Swallow {Petrochelidon alhi- 

 froris Say) 



English Sparrow {Passer domeslicus 

 Linnaeus) 



Totals. 



Nests 

 examined 



3 



2 



2 



1 



5 



25 



3 



54 



Infested 

 nests 



3 

 2 

 2 

 1 

 4 

 18 

 1 

 1 

 1 

 



33 



Uninfested 

 nests 





 

 

 



1 



7 

 2 

 4 

 6 

 1 



21 



Infesta- 

 tion 



100% 



100% 



100% 



100% 



80% 



72% 



33% 



20% 



14% 



0% 



61% 

 ;Average 



* A species closely related to Phormia chrysorrhea Meigen, the latter, according 

 to Dr. Townsend, being synonymous with Phormia sordida Zetterstedt and Phormia 

 splendida Macquart. 



