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light. Migrating beetles invariably check their rate of movement or come to 
a dead stop when a shadow from a cloud or other objects is cast over them. 
Examinations made in the early morning hours in lightly infested fields 
often fail to reveal a single beetle, but as the sunlight and temperature 
increase the beetles begin to move and are easily detected, many coming from 
the cracks and crevices in the soil and from around the base of the plants. 
Migratio n of the adults . — The migration is more or less a general 
dissemination away from the areas where the adults emerged. The beetles 
do not move any great distance per day but keep moving in the same general 
direction day after day. The migration was studied during 1938 by placing 
trap holes along barriers around an infested field. The peak movement of 
the beetles occurred on July 13-14 and the peak of emergence on July 12-14 in 
this locality. The daily rate of travel was studied by releasing a number 
of marked beetles at a given point and recording their recovery in traps 
at various distances from the release point. The field utilized for these 
studies was cropped to cotton and corn and had a fair growth of grass and 
weeds when the beetles were released. It was found that the average daily 
rate of travel was 16.8 yards. The seasonal movement covered from one-fourth 
to three- fourths mile, depending on the type of vegetation in the path of 
the beetles. The movement is greatest over areas bearing scant vegetation 
and least over areas covered with dense vegetation. The beetle's habit of 
investigating practically every plant in its path prevents it from moving 
any great distance. 
Parthenogenesis . — So far as is known there are no males. This insect 
reproduces parthenogenetically. L. L. Buchanan, of the Division of Insect 
Identification, dissected more than 2,300 adults collected on July 14, 1937, 
in the field in the Florala area and found that all individuals were females. 
A. N. Tissot, of the Florida Agricultural Experiment Station, examined about 
200 adults collected during 1937 in the Florala area and reported (Fla. Ent., 
vol. XXI, pp. 20-27, 1938) that all individuals were females. During 1937 
and 1938 more than 100 beetles were reared in individual containers or taken 
from their pupal cells within the soil and confined singly in the insectary 
in smell jelly glasses with soil and foliage. Every one of these individuals 
deposited fertile eggs. 
A bundance of adults . — In a heavily infested cotton field one man 
collected approximately 80,000 beetles from one-half acre in 4 hours on 
July 14, 1937. As the bag-and-hoop method was used for collecting the 
beetles shaken from the plants and only about two-thirds of the beetles 
were captured, they were present at the rate of about 240,000 per acre. 
The average population was 48 beetles per plant. Approximately 50 percent 
of the plants in this field had been destroyed by the larvae, and the stand 
was only 5,000 plants per acre. 
During the period immediately after emergence, July 7 to July 20, 
1937, it was common to find from 50 to 100 beetles per plant in the infested 
cotton fields, and from 150 to 200 beetles were taken from individual plants 
in the heavily infested portions of cotton fields. On July 10, 1937, 250 
beetles were taken from one cotton plant, 78 from one velvetbean plant, and 
