THE CONCHUELA. 



69 



These worked on different sections of the plantation and in several 

 gangs of from 6 to 50 boys each, the work of each gang being under 

 the direct supervision of a man selected for the purpose from among 

 the laborers. The time possible for the author to devote to this 

 phase of the investigation of the conchuela did not permit of as 

 detailed a study as was desirable, yet it is believed that the experi- 

 ments are by far the most extensive ever conducted along the line 

 of hand-collecting of insect pests. 



After testing various receptacles for containing the bugs as they 

 are collected in the field, a dipperlike tin vessel, with a cover con- 

 sisting of a detachable funnel, was devised^ and found to serve the 

 purpose in an ideal manner. The con- 

 structive details of this receptacle are 

 shown in figure 9. A slight jar of the 

 boll or leaf upon which the bug is rest- 

 ing is sufficient to cause it to fall through 

 the funnel into the chamber below, from 

 which there is practically no chance for 

 its escape until the receptacle is filled 

 to the opening. The contents should 

 then be emptied into a pail containing a 

 mixture of water and kerosene in the 

 proportion of two-thirds to one-third, 

 respectively. 



Results of experiments. — The removal 

 of many thousands of the conchuela 

 from the cotton fields could not have 

 other than direct beneficial results while, 

 as an experiment, useful information 

 concerning the practice of hand-picking 

 of plant-bugs was obtained. 



The greatest obstacle to be overcome 

 in order to obtain the best results from 

 hand-picking was found to be lack of thor- 

 oughness. There was much variation, however, in regard to this point 

 and it was soon evident that it is dependent almost entirely upon the 

 efficiency with which the boys engaged in picking the bugs were super- 

 vised. A series of examinations was made in two tablas of 120 acres 

 each for the purpose of determining the number of bugs present on 

 the plants before and after picking. It was found that in one tabla 

 about 21 per cent, and in the other about 33 per cent, had been re- 

 moved. From the fact previously stated that in clear weather fully 

 90 per cent of the bugs occupy conspicuous positions on the plants 

 it is evident that the lack of thoroughness in the above-mentioned 



Fig. 9. — Plan for the construction of a . 

 collecting can for use in hand-picking 

 cotton plant-bugs: A, Main part of can, 

 made of tin and with a wooden handle; 

 B , funnel-shaped cover; C, vertical pro- 

 jection showing cover with opening in 

 the center and vertical projection of 

 handle at right. (Original.) 



« Credit is due Messrs. Conduit and Vaughan for their ideas in this connection. 



