32 



of these points was satisfactorily determined, owing to the brief 

 period avaihible for this inA^estigation. As has been stated, the size 

 of the boll is an important factor; probably a single bug in a few 

 hours, or perhaps minutes, 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 dcA^elopment, perhaps when the boll is about three-fourths grown, 

 it is beyond the limit of danger of serious injury 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 : 



Results of cage tests witli Peniatoma, Jigata, 190 Jj. 



Cage 

 No. 



Num- 

 ber of 

 bugs. 



Apparent- 

 ly sound 

 bolls. 



When caged. 



When examined. 



Injured 

 bolls. 



Severely 



injured 



bolls. 



1 



5 

 6 



8 

 26 



Septembers.-- 





4 

 16 



2 



2 



September i 



rlo 













The cage tests were made in a portion of the plantation apparently 

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

 could be found Avhich was likel}^ to have been caused by such insects. 



Relation of Mesquite to Infested Fields. 



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

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

 1903, OAving to specially favorable weather conditions the crop of 

 mesquite beans Avas 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 Avay into the cotton fields in correspond- 

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

 at times AA^hen there Avere no green mesquite beans, and no specimens 

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

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

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

 Avhich Avas found on the ground among the dead leaA^es on March 8. 



Although no direct evidence could be obtained concerning the origin 

 of the large numbers of the insects AAdiich 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 betAveen 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. 



