32 



ot these points was satisfactorily determined, owing to the brief 

 period avaihdjle for this investigation. As has been stated, the size 

 of the boll is an important factor; })robal)ly a single bug in a few 

 hours, or i)erha})s mimites. can produce an injury to a boll one-fourth 

 or one-third grown which will prevent its developing perfect lint. 

 On the other hand, it seems that after the lint reaches a certain degree 

 of development, perhaps when the boll is about three-fourths grown, 

 it is beyond the limit of danger of serious injurj^ from the conchuela. 

 The following records show the only information obtained from the 

 cage tests relating to the question of how long after being attacked, 

 the injury to the boll appears : 



Re^nlti< of ciKje tests tritit Pcntutoinu lij/alu, IDOJ/. 



The cage tests were made in a i:)ortion of the plantation apparently 

 free from the conchuela and other bugs, and where no injury to bolls 

 could be found which was likely to have been caused by such insects. 



Relation of Mesquitk to Infested Fields. 



The co.ichuela is believed by Mr. Conduit to be identical with an 

 insect which breeds upon mesquite beans." In the early summer of 

 1903, owing to specially favorable weather conditions the crop of 

 mesquite beans was unusually large, and it is generally believed in 

 the Laguna district that an unusually large number of the conchuelas 

 developed in the mesquite, and upon the maturing and drying of the 

 beans the insects made their way into the cotton fields in correspond- 

 ingly large numbers. Both of the writer's visits to Tlahualilo, made 

 at times when there were no green mesquite beans, and no specimens 

 of P. ligata could be found in the mesquite or anywhere else except 

 in the cotton fields, nor could any remains of their immature stages 

 be found, except a batch of eggs from which the nymphs had emerged, 

 which was found on the ground among the dead leaves on March 8. 



Although no direct evidence could be obtained concerning the origin 

 of the large numbers of the insects which infested the cotton fields 

 in 1903, the statements of Mr. Conduit concerning the portions of 

 the estate Avhere the insects occurred in greatest numbers, both in 

 1903 and 1904, seem to show a connection between these portions and 

 the parts of the uncultivated land surrounding the estate on all sides, 

 upon which the mesquite growth was most abundant. 



o Since the above was written this has been verified by the writer. 



