16 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



this insect-damage (PL II, fig. 5). However, the fact that they have 

 been produced in some cases differentiates the injury by this Capsid 

 from that of all Pentatomids, Coreids, and Pyrrhocorids which has 

 come under the writer's observation. Investigations during the past 

 two years in many sections of Texas and in northern Mexico with 

 representatives of these three last-mentioned families of Heteroptera 

 have failed to show a direct connection between spots of any kind on 

 the outside of the carpels of the injured boHs and the insect's punc- 

 tures. In nearly all cotton fields bolls can be found which are marked 

 with reddish or brownish spots (PI. II, fig. 8), more frequently seen 

 on the parts of the boll not covered by bracts, and never showing on 

 the inside of the carpels. It is apparently an evidence of a physiolog- 

 cal disorder of little or no consequence, but in some cases these spots 

 have appeared to bear a relationship to the condition of the developing 

 lock. To determine if any such relationship existed in the case of 

 green bolls damaged by plant-bugs, 100 bolls were examined, with 

 the following results: 



Average number of spots in 25 bolls with slightly stained locks 2. 24 



Average number of spots in 75 bolls with badly stained locks 3 



Percentage of badly stained bolls without spots 10 



Percentage of slightly stained bolls without spots 46 



A second lot of green bolls picked from plants on July 11, 1905, was 

 examined and the results are here presented in tabular form. 



Table I. — Relation of external spots to j^lant-bug injury of cotton bolls. 



Number of external spots. 



Number of 

 bolls. 



Number of 

 bolls dam- 

 aged. 



Number of 

 bolls un- 

 injured. 



More than one 



17 

 11 

 10 



17 

 9 







One 



2 



None 



7 3 







Total . - - - - . 



38 



33 



5 







The punctures may be through the spot, but this is entirely acci- 

 dental. One boll of the above lot showing over 60 conchuela punc- 

 tures was found to have but three small external spots, while the 

 carpel of the lock most severely damaged was entirely free from dis- 

 coloration. Among those examined which showed but one external 

 spot, several were as badly damaged as any of the entire number. 

 From the foregoing observations we may conclude that the spots 

 here referred to with which every cotton grower is familiar do not bear 

 a direct relation to punctures by plant-bugs, for the spots may be 

 present on bolls which show no punctures, which in all cases are detect- 

 able when present as hereafter described, and may be absent on badly 

 damaged bolls. They are shown, however, to have a secondary 



