Williams' "The Aphididae of Nebraska" 23 



" Myzus oenotherae n. sp. No. 104. On Oenothera." 

 Two winged viviparous females and five immature individuals 

 on the slide. This may be the same as Sanborn's Myzus biennis. 

 Sanborn's figure of this latter does not agree in all respects with 

 his description of the same species. The description of biennis, 

 including the numbers of antennal sensoria and lengths of an- 

 tennal segments, agrees with that of Macrosiphum oenotherae. 

 In one specimen of the latter species vein M^ branches nearer the 

 tip and in the other it branches nearer the point where Mg.^ 

 branches. Cornicles with an indistinct reticulation at the tip 

 when viewed with a 5^ objective. This is a Macrosiphum and 

 not a Myzus as given by Mr. Williams. Camera lucida drawings 

 of the head, antenna, cornicle and style of the winged viviparous 

 female are given on Plate VII, figs. 114 to 116. 



81. Myzus plantagineus Passerini. 



82. M. potentillae Williams. 



" Myzus potentillae n. sp. No. 108. On Potentilla, A, 5/24, 

 '90." 



Two winged, two wingless adults, and several immature vivip- 

 arous females on the slide. 



Winged viviparous female: Antennae very tuberculate; segments III 

 and IV with numerous, irregularly placed, tuberculate sensoria, and seg- 

 ment V with 3 to 9 tuberculate sensoria; longer than body; measurements 

 of segments as follows : 



III IV V VI base VI filament 



0.59 0.355 0.25 0.089 0.87 mm 



0.62 0.328 0.27 0.097 0.78 mm 



0.64 0.346 0.27 0.106 0.80 mm 



Only one wing, of the four examined, has the media (discoidal) once 

 branched. In the original description Williams says " cubitus [= media] 

 often with but one branch." Length of cornicles, 0.21 mm; of style, 

 0.14 mm. 



Wingless viviparous female: Antennal segments III and IV bearing 

 many tuberculate sensoria. Measurements of antennal segments as 

 follows : 



275 



