Williams' "The Aphididae of Nebraska" 33 



excepting tip which is reticulated; length 0.80 mm. Style typical of the 

 genus Macrosiphum, length 0.34 mm. 



Wingless oviparous female: Antennae longer than body; segment III 

 with 4 to 6 circular sensoria in a row on the basal portion; measurements 

 of segments follow : 



Hind tibiae swollen and bearing many sensoria on the basal four fifths. 



Another slide labeled " Siphonophora pelargonii ? Kalt. No. 

 149. On Hollyhock, Ashland, Nov. i, 1890" contains one winged 

 female and three immature. The antennae of the winged speci- 

 men bears 16 to 20 sensoria on III and the usual ones on V and 

 VI ; antennae much longer than body ; measurements as follows : 



A^enation as described for winged individual on slide No. 148. 

 Cornicles reaching beyond tip of abdomen but not to tip of style, 

 the tips reticulated. 



The third slide labeled " Siphonophora pelargonii Kalt, No. 

 150. On Geranium in greenhouse, Omaha, Jan. 16, 1891 " con- 

 tains wingless viviparous females and immature. Antennal seg- 

 ment III bears 18 to 21 circular sensoria more or less in a row, 

 extending the entire length of the segment; total length greater 

 than that of body ; measurements as follows : 



Cornicles slender and reaching beyond tip of style ; subequal or 

 slightly shorter than segment III of antenna and at least twice 

 the length of style; imbricated to tip (no reticulation). 



This Geranium species agrees with specimens which I have col- 

 lected on Pelargonium in greenhouses but my winged specimens 



285 



