AND PROBLEMS IN SOUTHERN NIGERIA. 197 



The eggs are cream-coloured, about 0*6 mm. in length, and are laid in clusters 

 at the base of the boll, securely protected by the lint from sun and possible 

 enemies. The number laid by each female is not known for certain, but seems 

 small, about 20. At the beginning of December the small, reddish brown, wing- 

 less young have been found swarming and active in the bolls. 



There seems a decided preference for certain species of Hibiscus as food- 

 plants, for in the Nursery at Ibadan the ripening plants were found to be black 

 with these pests. The insects seemed to be feeding on all parts of the plant, 

 which is not the case with cotton. Their bush food-plants are not known. 



The security of the place of development greatly assists their multiplication. 

 The rate of increase is rapid, but whether owing to the number of eggs laid by 

 each individual, or to the number of generations per season, is uncertain. 



At Ugboha these insects occurred in amazing quantities. Several acres of 

 neglected cotton plants, with unpicked and late-ripening bolls, were literally alive 

 with the bugs, and gave some idea of what unchecked feeding and breeding could 

 produce. 



It is not safe at present to state the extent of the harm done by these insects ; 

 but their abundance indicates that very real damage is being done to the seeds at 

 least. Whether they stain the lint seriously cannot be said. 



The measures suggested to combat the Red Cotton Bug apply equally well 

 here. The sunning of the collected lint has been found to be especially efficacious. 



Boll-Worms. 



Three kinds of boll-worms have been studied from the cotton plots of the Agri- 

 cultural Department at Ibadan, namely, Diparopsis castanca, Hmp., Earias 

 biplaga, Wlk., and Chloridea obsoleta, F. Observations at Agege, and informa- 

 tion received at Ugboha (Eastern Province) point to their being widely distributed 

 throughout the Colony. 



The caterpillars bore into the unopened ripening cotton bolls and devour the 

 seeds inside, while Diparopsis castanca and Chloridea obsoleta are known to eat the 

 cotton flower-buds also. The larvae leave one boll for others and frequently all 

 the bolls on one tree are utterly spoilt. 



The moths are all nocturnal, but while the adult of Diparopsis castanca has 

 been captured at night, the other two have only been reared in the laboratory. 

 The earliest date of their appearance was found to be September. 



The only details of the life-history mentioned here are those noted in the 

 Colony. Diparopsis castanea is discussed in the " Third Report of the Wellcome 

 Research Laboratories, Khartoum," and Chloridea obsoleta in " Bulletin 50 of the 

 Department of Agriculture, U.S.A." 



Diparopsis castanca, Hmp. (Plate XXIV, fig. 2). 



Some of the following information is derived from the notes of Mr. C. W. 

 Jemmett, Entomologist in Southern Nigeria from 1909-11. 



The eggs are very small and blue and are laid on the leaves in September. 

 The larva is pale green, with red blotchy markings, and grows to about one inch. 

 When full-grown it burrows a few inches into the soil and makes an earthern 

 cocoon. The pupa is pale yellow, and the pupal period occupies from 12 to 19 

 days. 



