44 BULLETIN 918, U. S. DEPARTMENT OF AGRICULTURE. 



as it is in Egypt in May and June (107° and 111° F.) and our bolls 

 received some protection from the sun by the screen covering of 

 the irrigated bolls and the cheesecloth covering over the nonirri- 

 gated bolls. Furthermore, our bolls were probably kept wetter 

 during the 30 days when they were wet than Willcocks's were, but 

 his were kept wet for a longer time. There was but very little larval 

 emergence in any of our bolls. This is shown by the large numbers 

 of dead larvae found in situ in the earlier examinations, when they 

 were still recognizable, and by the few larvae or pupal skins found in 

 the surrounding soil. There was more larval emergence from the 

 bolls in the irrigated plots where 12 pupal skins were found in the 

 soil than in the nonirrigated where only 2 or 3 were found. About 

 half of the larvae recovered in the bolls were in the lint, but no count 

 was kept of this point and it is not known whether there were more 

 than are usually found in lint in the bolls in the fields during the 

 fall or not. In the case of the double seeds in the irrigated plot the 

 following note was made: "Earthen cells were noticed in a few 

 instances, apparently some of the larvae left the seed." In the double 

 seed on the nonirrigated plot 4 pupal skins were found in the soil. 



On March 11, 1919, 100 bolls which were picked on December 7, 

 1918, and stored in the laboratory till this date were buried 1 to 2 inches 

 deep in a box of soil and wet thoroughly. The box was sprinkled 

 often enough to keep it thoroughly wet for 30 days. On April 11 

 the contents were carefully examined and 35 live larvae and 90 dead 

 larva? were found in the bolls and only 4 larvae and 2 pupae in the 

 soil. Willcocks (7) found a very sudden increase in the number of 

 larvae emerging to the surface in a box of bolls buried in dry soil and 

 watered in the spring. 



Unfortunately a sufficiently large sample of bolls for our check 

 was not examined at the beginning of the experiment to determine 

 the mortality until this date, and the check sample examined at the 

 end of the experiment contained more live larvae than at the begin- 

 ning. The indications were, however, that the treatment had killed 

 a large number of the larva?. The bolls were totally rotted and 

 larva? which were dead at the beginning of the experiment were 

 unrecognizable at the finish. 



MORTALITY OF HIBERNATING LARVAE IN STORED SEED. 



The number of larvae found in the ginned seed is very small com- 

 pared to the number found in the bolls when the cotton is picked. 

 In the Laguna the seed cotton is passed through cleaners or beaters 

 before it goes to the gins to remove the trash and dirt. This causes 

 most of the larvae to leave the lint and many are undoubtedly driven 

 from the seed also during the process. Larva? are thrown out by 

 the thousands with the trash that comes from the later pickings, and 

 in some cases the pile of trash and the sides of surrounding buildings 



