382 



747. , and Sterling, W. L. 1974. Aggregation indices of cotton arthropods 



in Texas. Environ. Fntomol. 3: 598-600. 

 Two indices were used to quantify the aggregation of cotton arthropods: the para- 

 meter K of the negative linomial distribution and Morisita's index of dispersion 

 16. Using frequency distribution data the average values of these indices were 

 calculated. In general there was close agreement betweeii K and 16. Cotton flea- 

 hopper, Pseudatomoscelis seriatus (Reuti^r) , njrmphs were more aggregated than flea- 

 hopper adults. A greater degree of aggregation was observed for boll weevil, 

 Anthonoraus grandis Boheman, eggs than for boll weevil adults. Bollworra, Hellothis 

 zea (Boddie), and tobacco budworm, _K. v irescens (F.), eggs exhibited more aggrega- 

 tion than Heliothis spp. larvae. Aggregation continued to decrease as the Helio- 

 this spp. larvae became full grown. Among the predatory cotton arthropods, lady 

 beetles and minute flower bugs, Orlus spp., displayed the greatest amount of aggre- 

 gation. Big-eyed bugs, Geocoris spp., were less aggregated and the spatial dis- 

 tributions of spiders were the least aggregated of the predatory arthropods. 



748. , and Sterling, W. L. 1975. Sequential sampling cotton squrtres damaged 



by boll weevils or Heliothis spp. in the Coastal Bend of Texas. J. Econ. f, 



Entomol. 68: 543-545. 

 Sequential sampling plans based on the binomial distribution were developed for 

 sampling squares (floral buds) damaged by the boll weevil, Anthonomus orandis 

 Boheman, or the bollworm, Heliothis ::ea (Boddie) ^ and the budworm, H. virescens 

 (F.). These plans were compared to a f ixed-srmple-size (100 squares) method of 

 sampling damaged squares. Field trials indicated that the use of sequential 

 sampling plans provided ca. 50% savings in time over the fixed-sample-size 

 method. The treatment, decisions were similar for both methods. 





