312 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



transported long distances and to establish themselves in new dis- 

 tricts which furnish sufficient humidity coincident with food-supply 

 during any considerable portion of the year. 



Capacity for Damage 



The capacity of the weevil for damage to the cotton crop is not so 

 great in the Peruvian coast region as it would Ije in a tropical region 

 that is truly humid throughout the year. But its damage varies 

 considerably within this region, according to a variety of factors. 

 Other things being equal, its damage in the various districts is directly 

 proportionate to the annual duration of sufficient relative humidity 

 to maintain its activity. It does the most damage in those districts 

 where the l)ulk of the squares are formed during the most humid 

 season of the year, providing that the temperature is sufficiently 

 high during that season to accelerate rather than retard its develop- 

 ment. From these facts it is evident that the damage is high in Piura, 

 and proba])ly still higher in the central coast region of Peru. Its 

 average damage for the whole coast region must be considerably less 

 than that of the boll-weevil in the more humid region of the southern 

 United States, but it can hardly fall below 20 per cent. This means 

 an annual loss to Peru from the weevil of about £400,000. 



Work for the Future 



Future work should consist of fostering the parasites of the weevil 

 so far as practicable in the different districts; introducing and estab- 

 lishing one or both of the two species of ants above mentioned, Solenop- 

 sis geminata and Edatomma tuber culatuvi, for attacking the early 

 stages and adults of the weevil respectively, first ascertaining whether 

 these two species are incompatible with each other or whether they 

 may be maintained side by side in harmony, in the former case select- 

 ing the more effective of the two; and working out the details of the 

 cultural control measures already outlined. 



In order to carry these lines of work through intelligently, full data 

 are needed on humidity and temperature ranges of the weevil and its 

 enemies; and on both cotton varieties and cultural and irrigation 

 methods adapted to the soils and climatic conditions of the different 

 districts in the coast region. Such data can only be obtained by exe- 

 cuting well-planned series of experiments in the laboratory and in- 

 sectary in intimate connection with control work in the field. 



