SECONDARY PAEASITES. 



125 



Toxoptera graminum 1 



'avenaphis. . Macrosiphum granaria Buck. 

 confusus. . . Macrosiphum erigeronensis Thos. 

 testaceipes . . Aphis avenx Fab . 



Aphis gossypii Glov. Aphis sp. 



Aphis maidis Fitch. 



Aphis maidi-radicis Forbes. 



Aphis medicaginis Koch. 



Aphis oznotherx Oestl. 



Aphis rumicis Linn. 



Aphis setariae Thos. 



Macrosiphum viticola Thos. 



Macrosiphum granaria Buckt. 



Melanozantherium sp. 

 Aphidius. . J Macrosiphum sp. on black gum. 



Myzus ribis Linn, on currant. 



Myzus sp. on Hosackia glabra. 



Macrosiphum sp. on Abutilon. 



Macrosiphum cucurbitae Thos. 



Aphidid on Ampelopsis sp. 



Aphidid on Baccharis viminalis. 



Aphidid on Capsella bursa-pastoris. 



Aphidid on Eragrostis sp. 



Aphidid on Kochia sp. 



Aphidid on locust. 



Aphidid on peach. 



Aphidid on pigweed (?). 



Aphidid on plum. 



mali Aphis brassicas Linn. 



Aphis monardae Oestl. 



Aphis sacchari (?) Zehntn. 



Aphis setariae Thos. 



Colopha eragrostidis Middl. 



Myzus mahaleb Boyer. 

 Aphelinus.J Pemphigus frazinifolii Riley. 



Macrosiphum rosae Linn. 



Schizoneura americana Riley. 



Schizoneura lanigera Haussm. 



Tetraneura colophoidea (?). 



nigritus Aphis setarise, Thos. 



semiflavus.. Aphis maidis Fitch. 



Aphis gossypii (?) Glover. 



Chaitophorus viminalis Mon. 



Myzus persicx Sulz. 



SECONDARY PARASITES. 



Megorismus sp. 



Species of the genus Megorismus, it appears, have been previously 

 considered as primary parasites. Mr. Parks, however, has con- 

 ducted some experiments with a species (fig. 34) at Wellington, 

 Kans., and his results clearly indicate that in this case it is a sec- 

 ondary parasite. In no instance could he rear it from aphidids 



