BIOLOGICAL STUDIES ON THREE APHIDID.E. 137 



black. Measurements (alcoholic specimens) : Length of body, 1.686- 

 1.745 mm.; width, 0.909-0.945 mm.; antenna. I. 0.081 mm.; IT, 0.054 

 mm.; Ill, 0.200 mm.; IV, 0.136 mm.; V. 0.100 mm.; VI, basal, 0.109 

 mm.; filament, 0.181 mm.; total, 0.861 mm.; cornicle, 0.082 mm. 



Eggs. — Elliptical-oval, yellow or greenish when first laid, grad- 

 ually darkening to a jet-black. In spring just before hatching the 

 eggs change from black to pale green. Length, 0.782 mm.; width, 

 0.391 mm. 



BIBLIOGRAPHY." 



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

 <Journ. III. State Agr. Soc, Springfield, pp. 8-13, flgs. I, III, IV. 



Aphis maidis (?) infests the roots of young Indian corn as well as the stems 

 of the roasting ears. This is the first notice of the occurrence of the root form. 



1862. Walsh, B. D. — On the genera of Aphidse found in the United States. 

 <Proe. Ent. Soc. Phila., Philadelphia, Pa., Vol. I, pp. 300-301, flgs. 

 I, III, IV. 



Aphis maidis ( ?) root form. Compares it with the aerial form. Food 

 plant, maize. 



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

 <Trans. 111. State Agr. Soc, Springfield, Vol. V, pp. 491^97, figs. I, 

 III, IV. 



A reprint of the article in Journal of the Illinois State Agricultural Society 

 (loc cit.) . 



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

 <Trans. 111. Hort. Soc, CThicago, Vol. X, n. s., p. 167. 



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



1878. Thomas, Cyrits. — List of the Aphidini of the United States. <I11. State 

 Lab. Nat. Hist., Bloomington, Vol. I, Bui. 2, p. 12. 



Lists Aphis maidis as being found on the tassel, ear-stalks, and roots of 

 Indian com. 



1578. Thomas, Cyrus. — Seventh Report of the State Entomologist of Illinois. 



<App. : Trans. Dept. Agr. 111. for 1877, Springfield. Vol. XV, pp. 7.5- 

 78, fig. 18 (I, III, IV). Separate: Springfield, 111., 1878. 



Gives characteristics of the aerial and root forms as presented by Fitch and 

 Walsh, and also a description of specimens which he obtained the previous sum- 

 mer from a different part of the plant (tassels). Possible treatment against 

 aphides in small patches of corn is given. Appends notes from correspondents 

 concerning serious damage done to corn in 1874 and 1877 in Menard and Stark 

 counties, Illinois. 



1579. Thomas, Cyrus. — Eighth Report of the State Entomologist of Illinois. 



<App. : Trans. Dept. Agr. 111. for 1878, Springfield, Vol XVI, pp. 89- 

 91, fig. 14 (I, III, IV). Separate: Springfield, 111., 1879. 



Same as' in Seventh Report of the State Entomologist of Illinois, except that 

 no remedies are mentioned (loc. cit.). 



"This bibliography is practically complete, and contains a number of refer- 

 ences not found in the Bibliography of Economic Entomology, by Henshnw and 

 Banks. Those titles which have been inaccessible are marked with an asterisk. 

 Those which are considered the most important have the date preceding them in 

 it:ilics. 



61017— No.12, pt 8 3 



