BIOLOGY OF THE MEXICAN COTTON" BOLL WEEVIL. 3 



In 1914 the life history and habits of the Arizona weevil were 

 studied under natural conditions in the mountains near Tucson, Ariz. 

 These studies are discussed in two papers. 7 



Thus it is seen that these studies embrace a wide range of time and 

 conditions. In fact, the conditions of humidity, rainfall, tempera- 

 ture, altitude, soil, etc., include practically all extremes found in the 

 cotton belt. 



SCOPE OF THE PRESENT LIFE-HISTORY STUDIES. 



The biological studies of the boll weevil at Madison, Fla., during 

 the year 1918, included a thorough study of the boll weevil under 

 outdoor insectary conditions on both upland and sea-island cottons. 

 The main object of this study was to determine the difference, if any, 

 in the weevil's biology on the two kinds of cotton. During the month 

 of August, 1918, a small series of experiments was made to deter- 

 mine the length of the developmental period of the weevil from egg 

 to adult under actual field conditions. The results of the field studies 

 indicated conclusively that a wide variation existed in the length of 

 time required for the developmental period of the weevil under 

 insectary conditions compared with the true developmental period 

 under normal field conditions. Consequently the studies in the 

 biology of the weevil during the year 1919 were arranged to include 

 a thorough study of the field biology of the boll weevil. Insectary 

 studies in the biology of the weevil were conducted at the same time 

 the field tests were under observation, to serve as a check. 



METHODS USED IN THE STUDY OF THE BOLL WEEVIL UNDER 

 OUTDOOR INSECTARY CONDITIONS. 



The numerous experiments of 1918' were conducted in a specially 

 constructed outdoor insectary at the Madison, Fla., laboratory (fig. 

 8). The sides of the insectary building were constructed entirely 

 of 16-mesh galvanized wire screen; from the floor to the ceiling, 

 which permitted free air circulation at all times. The roof of the 

 insectary building extended 2 feet over the sides of the building, 

 preventing the direct rays of the sun from touching any of the breed- 

 ing jars. All the insectary breeding work was conducted in glass 

 tumblers half filled with white sand. The sand was kept constantly 

 moist. Lantern globes with cheesecloth covers were) used for the 

 longevity experiments. 



7 Coad, B. R. Relation of tbo Arizona Wild Cotton Weevil to Cotton Planting in the 

 Arid West. U. S. Dept. Agr. Bui. 233, 12 p., 4 pi. 1915. 



Coad, B. R. Studies on the Biology of the Arizona Wild Cotton Weevil. U. S. Dept. 

 Agr. Bui. 344, 23 p., 2 pi., 1 fig. 1916. 



