NATURE OF INJURY. 19 
eration on the inner side of the carpel, such as has been described, 
indicates an injury to the seed or discoloration of the lint directly 
opposite. When a seed of a rapidly growing boll is fed upon at first 
the stimulation, probably partly mechanical and partly due to salivary 
fluids of the bug, causes an increase in the flow of sap to the injured 
seed, causing a characteristic watery appearance. The seed after- 
wards gradually becomes discolored (PL II, figs. 4,6) and proliferous 
tissue is extruded from it in some cases. Punctures near the tip of 
the lock are most effective in destructiveness ; in one case (PI. Ill, 
fig. 8) 4, 6, 16, and 10 punctures per lock, respectively, were found to 
have produced proliferation from the seed nearest the tip of the boll 
in each lock and would have prevented the opening out of the cotton 
if it had been allowed to mature. This is equivalent to complete 
destruction of the boll. The lint surrounding the point where the 
insect's mouth-parts enter turns yellowish, and, if the injury is severe, 
finally becomes a dirty brown and decays (PI. II, figs. 1, 2; PI. 
Ill, figs. 1-8), which probably is the condition Glover referred to as 
"the rot." 
As the great majority of the punctures are made on the outer half 
of the bolls, it is there that staining is most frequently found. 
In general bolls damaged by plant-bugs when open (PI. Ill, figs. 
1-5; PI. IV) are characterized by shriveled locks and only partial 
spreading of the carpels. The entire lock may become a brownish 
shriveled mass or the shriveling may be confined to the outer tip. 
Again, locks may be perfect except for a small stained patch of lint, 
which, however, might offset the value of the unstained product. 
Seeds in nearly mature bolls may be destroyed without the surround- 
ing lint becoming badly stained. Consequently where Heteropterous 
cotton pests are abundant, there is a reduction in the percentage of 
seed capable of germinating. This phase of the subject of plant-bug 
damage has received no especial attention. 
Proof that described injury is due to plant-bugs. — The evidence that 
plant-bugs cause injury such as described above amounts to positive 
proof. Sufficient evidence was given by the author in a previous 
report and, although much more might be added, it is unnecessary to 
more than summarize the facts there presented: 
1. In a field where the number of conchuelas averaged about 1 5 
per acre and the number of other plant-bugs was a negligible quantity. 
a specimen of the species named (Pentatoma ligaia Say) was known to 
have fed on a single boll for over 36 hours. After several days, 
during which no bugs were found on this plant, the 15 bolls found on 
this plant were cut open and examined, with the result that only the 
one upon which the insect was known to have fed showed the injury 
described. 
