62 PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



Table XXIII. — Abundance of Pentatomids, Zaragoza B, July 25, 1905. 



Tabla. 



Number 

 of plants 



Percent- 

 age of 



plants 

 infested. 



Number of 



adults P. 



ligata per 



row. 



Number of 

 adults P. 

 sayi and 



Thyantasp. 

 per row. 



Number of 



adult Pen- Number of 

 tatomids 

 per 100 



plants 



Egg- 

 nj-mphsP. batches 

 ligata per P. ligata. 

 row. a 



Total.... 

 Average. 



310 

 227 

 247 

 232 

 254 

 270 

 314 

 213 

 209 



6.4 

 1.3 

 1.6 

 2.1 

 3.1 

 3.3 

 6.0 

 6.1 

 3.8 



10.3 



112 



1.8 



12 



2.4 







5.6 







4.3 







5.9 







13.7 







9.6 







11.9 







2,276 

 255 



3.7 



164 

 18.2 



65.5 

 7.3 



12 2 

 1.33 



a Small figures indicate the instars. 



Thyanta sp. 



Pentatoma sayi. 



Table XXIV. — Abundance of Pentatomids, Zaragoza B, August 1, 1905. 



Tabla. 



Number of 



plants in 



row. 



Percentage 

 of plants 

 infested. 



Number of 

 adults of 

 P. ligata 

 per row. 



Number of 



adults 



(Table XXIII) 



P. sayi and 



Thyanta per 



row. 



Number of 

 adult Pen- 

 tatomids 

 per 100 

 plants. 



Number of 

 nymphs 

 P. ligata 



per row.o 



1 



301 

 236 

 265 

 308 

 303 

 275 

 371 

 232 

 170 



3.0 

 2.1 

 1.1 

 1.0 

 3.9 

 1.1 

 .5 

 4.3 

 1.1 



13 

 6 

 3 

 3 



10 

 3 

 2 



18 

 3 





 

 

 

 2 

 

 

 



4.3 

 2.5 

 1.1 

 1.0 

 4.0 

 1.1 

 .5 

 7 7 



12 



1^ 



13 

 13 14 



21 1* 

 

 

 25 2 1 

 



2 



3 



4 



5 



6 



7 



8 



9 



1.8 



Total.... 

 Average. . 



2,461 

 273.4 





61 



6.8 



2 

 0.2 



24.0 



33 1 

 3. 0. 1 



2.0 



a Small figures indicate the instars. 



The observations in Zaragoza B were niade partly as a check on 

 those raade in Ceceda A, tahla 14. In the latter block a large per- 

 centage of the bolls had already been ruined and probably rendered 

 less attractive as food for the bugs. There seemed to be a possibility 

 that the decrease in numbers during the last 10 days of July was due 

 to migration of the adults to other fields. In Zaragoza B, tablas 1-9, 

 the cotton was in such condition on the average that it is improb- 

 able that a scarcity of suitable food supply could have impelled a 

 migration. The data, moreover, on the numbers of eggs and nymphs 

 found in the different tablas give strong indications that the infesta- 

 tion had progressed from tahla 1 toward 9 and that it had been, on the 

 whole, recent. If the decrease in numbers of the adult conchuelas and 

 other species of Pentatomids in Ceceda A, tahla 14, had been due to a 

 migration, a similar decrease would have been unlikely to have 

 occurred in the planta cotton in Zaragoza where the food supply was 

 ample. The planta cotton in Ceceda A, tahla 16, separated from 



