800 Journal of Agricultural Research vol. vi, no. 21 



Pupae were found in the cage on June 27 and the adult moths began to 

 issue on July 8. The generation series was continued in another cage 

 in which moths issued from July 8 to 10, eggs were found on July 14, 

 larvae as early as July 20, and the first adults on August 30. These 

 adults, issuing between August 30 and September 8, were similarly con- 

 fined, and eggs were first noticed on September 25 and larvae on Septem- 

 ber 28. During the winter of 1915-16 they survived as partially grown 

 larvae and completed their growth in April, 191 6. Thus, it is observed 

 that in the latitude of La Fayette three complete generations may occur 

 annually, and from numerous observations of 1914 and 191 5 it is evi- 

 dent that in some seasons a partial fourth generation may be present. 

 Likewise, the overlapping of generations may account for a partial 

 fourth, although a complete fourth generation is seldom, if ever, pro- 

 duced in this latitude. 



MOLTING AND FEEDING HABITS 



The records of molts and of foliage eaten were made with larvae con- 

 fined in individual cages, three types of cages being used, namely, tin 

 boxes, glass test tubes, and lantern globes (PI. CVII, A). The tin boxes 

 used for individuals 1 to 48 and 77 to 132 were of the common salve-box 

 type, a 1 -ounce size being used for the earlier stages and a 3-ounce size 

 after the larvae were about half grown. Individuals 49 to 76, inclusive, 

 were reared in ordinary lantern-globe cages, with cheesecloth tops, placed 

 on paper-padded saucers and containing corn foliage in bottles of water. 

 Individuals 133 to 153 were reared in cotton-stoppered test tubes, which 

 measured approximately 6 inches in length and 1 inch in diameter, 

 smaller vials having been used for the first few instars. A single larva 

 recently hatched was placed in each cage and fresh corn foliage given it 

 as necessary. Frequent examinations were made to obtain as nearly as 

 possible the exact hour of molting. Foliage uneaten was pressed, and 

 from this the total amount eaten was computed for each larval instar, 

 using for this purpose ordinary plotting paper squared to hundredths of 

 an inch, by means of which a fairly accurate record of foliage eaten to 

 thousandths of a square inch was obtained. 1 



The tin-box cages, 1 to 48 and yj to 103, were kept indoors, and the 

 lantern -globe cages, 49 to 76, and vial cages, 133 to 153, were kept on a 

 latticed porch and were therefore under more nearly normal outdoor con- 

 ditions. As the experiments were conducted for the most part during 

 September and October, the nights were much cooler for the individuals 

 on the porch, resulting in a noticeably longer life-cycle period for these 

 than for the individuals kept indoors, where the coolness of the nights 

 was much less evident. 



1 The authors take this occasion to acknowledge their indebtedness to Mr. T>. G. Tower, of the Office of 

 Cereal and Forage Insect Investigations, who assisted in measuring the pressed foliage and in making 

 counts of eggs in the bodies of the moths. 



