BIOLOGICAL STUDIES ON THREE APHIDID^. 151 



black. Thorax and legs black. Abdomen pale bluish green. Three 

 black spots on each side of the bod}" and anterior to the cornicles, 

 and a black basal spot surrounding each cornicle. Posterior to the 

 cornicles are 2 black spots, one on each side, and also 8 more or less 

 distinct transverse black bands. Cornicles black, slightly incrassate 

 at middle, dilated at apex. Distal half of clorsally curved style 

 black, and the remainder margined with black to the base. Measure- 

 ments (alcoholic specimens): Length of body, 1.709 mm.; width, 

 0.618 mm. ; wing expanse, 5.786 mm. ; antennae, I, 0.065 mm. ; II, 

 0.057 mm.; Ill, 0.293 mm.; IV, 0.154 mm.; V, 0.154 mm.; VI, basal, 

 0.106 mm.; filament, 0.228 mm.; total, 1.057 mm.; cornicles, 0.130 

 mm. ; style, 0.081 mm. 



Pupa of winged female. — Body pale green. Head dark brown, 

 with a more or less distinct median white line. Antenna^ darker, 

 at either end. Antennae with a sensorium at the end of V, and 2 or 

 more at the distal end of the basal portion of VI. "Wing-pads, tip of 

 abdomen, and cornicles black. Legs dark, almost black. Cornicles 

 noticeably incrassate at middle and slightly dilated at the tip. Meas- 

 urements (alcoholic specimens) : Length of bodj^, 1.999 mm.; width, 

 0.799 mm.; antennae, I, 0.067 mm.; II, 0.057 mm.; Ill, 0.183 mm.; 

 IV, 0.125 mm.; V, 0.098 mm.; VI , basal, 0.084 mm.; filament, 

 0.159 mm. ; total, 0.773 mm. ; cornicles, 0.155 mm. 



BIBLIOGRAPHY. 



1856. Fitch, Asa. — The maize aphis. Aphis maidis, n. sp. <Secoucl Report, 

 Ins. New Yorli State, Albany, pp. 318-320. 



Describes the larva and the wingless and winged viviparous females. Food 

 plant, maize. 



1862. Walsh, B. D. — Plant-Iice — the corn-root louse. A new enemy to the 

 corn. <Jovu-n. 111. Agr. Soc, Springfield, pp. 8-13, Figs. I, III, IV. 



Reports finding an aphis on roots of corn whicli agreed " tolerably well " 

 with Aphis maidifi Fitch, and therefore he concluded that the root and 

 aerial forms were probably the same species. 



1862. Walsh, B. D. — On the genera of Aphida? found in the Tnited States. 

 <Proc. Ent. Soc. Phila., Philadelphia, December, 1862, Vol. I, pp. 300- 

 301, Figs. I, III, IV. 



Describes root-aphis as Aphis maidis (?), comparing with Fitch's descrip- 

 tion of that species. 



1865. Walsh, B. D. — Plant-lice — the coi-n-root louse. A new enemy to the 

 corn. < Trans. 111. Agr. Soc, Springfield, Vol. V, pp. 491-497, Figs. I, 

 III, IV. 



A reprint of the article in the .Tournal of tJie Illinois State Agricultural 

 Society. (Loc. cit.) 



1876. Thomas, Cyrus. — Notes on the plant-lice found in the United States. 

 <Trans. 111. Ilort. Soc, Chicago, Vol. 10. n. s., p. 167. 



General notes on the root and aerial forms of Aphis maidis Fitch. 



