46 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 
Table XX. — Summary of laboratory feeding records on the conchuela, Lot A. 
Place. 
Time. 
Per cent feed- 
ing in daylight. 
Per cent feed- 
ing at night. 
Per cent feed- 
ing, day and 
night. 
Tlahualilo, Durango, Mexico 
Dallas, Tex 
Julv 20-22,1905 
Sept. 4-8, 1905 
59.4 
27.2 
89.8 
62.5 
74.6 
A comparison of Tables XVII and XVIII shows a close corre- 
spondence between the laboratory and field observations on the 
amount of time the adults spend in feeding during daylight. The 
fact that in the field the conchuela feeds almost constantly after sun- 
set has already been recorded. We may safely assume that the 
adults feed for fully as large a percentage of the nighttime in the 
field as in the laboratory. Considering, therefore, that 90 per cent 
of the night (Table XVIII), and 66 per cent of the day, is spent in 
feeding, the percentage of the calendar day spent in feeding at the 
times and places of these observations was approximately 78. 
Table XX shows a difference between the same lot of insects 
which is probably attributable to the difference in age of the speci- 
mens. Difference in temperature could have had no appreciable 
effect as it was slight, the average daily mean at Tlahualilo on the 
days of the observations being 76° F. and at Dallas 79° F. 
Method of attack. — For locating the position for piercing the carpel 
of a cotton boll the conchuela makes use of its antennae and tip of 
the rostrum. As in other Heteroptera, the rostrum is used only as 
a guide for the threadlike setae and is never forced into the object 
upon which the insect may feed. As the setae sink into the boll the 
rostrum bends at the joint between the first and second segments, 
being directed backward. The setse at the same time are freed from 
the rostral groove of the basal two segments, and as these two seg- 
ments fold together, this allows a greater depth of penetration. 
Next, the apical or fourth segment is bent or folded back leaving the 
setse in the rostral groove only at the angle between the third and 
fourth segments. In this position the rostrum forms a letter "Z./' 
the upper angle representing the joint between the second and third 
and the lower angle the joint between the third and fourth segments. 
Feeding may be continued with the rostrum in this position or the 
rostrum may be freed entirely from the setae and directed straight 
back along the middle of the venter in the usual position it occupies 
when the insect is resting or crawling. The insect may therefore use 
practically the entire length of the setae to penetrate through the 
carpel and the developing lint to the cotton seed. This length is 
about one-fourth of an inch. When feeding, the bug alternately 
a Bui. 54, Bur. Ent., U. S. Dept. Agr., p. 26, 1905. 
