40 



concei'ning the life history and habits of the insect, and to verif}^ or 

 disprove what had been previous!}^ written concerning these points. 

 The results of this investigation by Professor Mally are presented in 

 Bulletins 24 and 2y, old series, of the Division of Entomology, and 

 were issued in 1891 and 1893, respectivel3^ 



Many detailed observations on the injuries to corn, cotton, and other 

 plants were made, and a S3^stematic series of experiments was con- 

 ducted with various insecticidal substances in order to determine their 

 possible value in bollworm control. The value of corn as a trap crop 

 is demonstrated and a definite plan is presented for its utilization by 

 planters. Experiments with bacterial diseases were conducted, and 

 the uselessness of attempts to attract moths to lights and poisoned 

 sweets, as previously recommended, is pointed out. The reports 

 together cover 123 pages, and bring together the important facts then 

 known concerning the cotton bollworm and present for the first time 

 results of any considerable experimental work. 



Frequent mention has been made of the bollworm as injuring cotton, 

 corn, tomatoes, or other crops in the bulletins and reports from the 

 office of the Entomologist of this Department, and recently (1896) a 

 full account of this species, b}" Dr. L. O. Howard, has been distributed 

 in Bulletin 33 of the Office of Experiment Stations," which was issued 

 in revised form in 1897 as Farmers' Bulletin 47, "Insects aflfectingthe 

 cotton plant.'- 



In spite of the work of the Department on the bollworm, but little 

 progress had been made by the planters in its control. The recent 

 increase of the ravages of the pest in certain parts of the cotton belt, 

 notably in Texas, led to provision by Congress for another investiga- 

 tion, and the present paper is a final report on this the fourth specific 

 investigation of the species. The present investigation was begun in 

 the spring of 1903, and continued to December 31, 1904. Reports of 

 field work have already been published in Farmers' Bulletins 191 and 

 212 of this Department. 



LIFE HISTORY. 



SUMMARY. 



The eggs of the bollworm (PI. HI, fig. 1) are deposited by the boll- 

 worm moth upon the food plants of the larvae, which are preferably 

 corn and cotton, or less commonly tomato or tobacco. Each female 

 may lay from 500 to 3,000 eggs, which she deposits singly in a more 

 or less promiscuous manner over the plants, more especiall}^ on the 

 silks of corn and the squares of cotton. During the warmer parts of 

 summer the eggs hatch after two or three days and the larvae begin 

 feeding. On corn they attack the tender bud in the spring and the 



«The Cotton Plant, pp. 328-333. 



