86 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 
Records based upon 14 batches of eggs deposited in the laboratory 
indicate that the average number of eggs deposited per batch is high 
as compared with most Pentatomids. These records gave an average 
of 31.4 eggs per batch, the range in number being from 10 to 42. 
In its selection of food plants Thyanta custator has thus far exhibited 
a preference for grains and cotton, although this may be only the nat- 
ural consequence of the fact that these are the principal crops grown 
in the section of the cotton belt where this Pentatomid is most abun- 
dant. At Tlahualilo, Durango, Mexico, where this bug was common 
in July, 1905, it was not found on alfalfa as were several other cotton- 
infesting plant-bugs, nor has it thus far been reported as occurring in 
alfalfa fields in Texas. A specimen of Thyanta custator in the fifth 
nymphal instar, immediately after being brought into the laboratory 
from the cotton field, fed upon eggs of the conchuela, exhibiting the 
only instance of a predatory habit which has been observed in this 
species. 
In the cotton fields this bug is commonly found feeding on the 
cotton squares and bolls— when feeding being frequently completely 
hidden by the bracts. This habit of concealment, together with its 
small size and inconspicuous color, makes it much more difficult of 
detection when present on cotton plants than are the other cotton- 
infesting Pentatomids which have been dealt with in the foregoing 
pages. The preference of the bug for the bolls over other portions of 
the cotton plant is fully as well marked as it is in the case of the 
conchuela. 
Gregariousness is also as well marked a characteristic of this species 
as of the conchuela. 
In October, 1897, Mr. J. D. Mitchell, in testing, at Victoria, Tex., 
the possibility of trapping the cotton boll weevil by lights, captured 
4 specimens of Thyanta custator in a one-night trial of 3 lights. a A 
specimen was taken at a light by Mr. J. C. Crawford at San Antonio, 
Tex., in May, 1905, and one by Messrs. Crawford and Pratt at Cotulla, 
Tex., on May 12, 1906. It is possible that trap lights might be suc- 
cessfully used against this insect in badly-infested fields of grain or 
cotton, for in the localities above mentioned where specimens have 
been captured by this means the species is comparatively scarce and 
the chances of capture proportionally reduced. 
SEASONAL HISTORY. 
The writer has found Thyanta custator in cotton fields in greatest 
abundance in September and October. In view of its occurrence in 
more or less destructive numbers in grain fields in northern and north- 
western Texas it seems likely that the time of its appearance in great- 
est numbers in cotton fields may be dependent upon the harvesting 
a Bul. 18, Div. Ent., U. S. Dept. Agr., p. 88, 1898. 
