THE RICE MOTH. 13 



Hydrocyanic-acid gas, it must be stated, is the most poisonous 

 substance in common use,' but it is still employed very extensively 

 in fumigating mills and dwellings, and if the directions in the 

 bulletins cited are carefully carried out there is really no danger to 

 human beings. 



CABBON DISXJLPHID. 



Before the general adoption of hydrocjanic-acicl gas as a means 

 of fumigating buildings, carbon disulphid was considered a standard, 

 and it is still of value, particularly on a small scale, as a substitute 

 for hydroc3"anic-acid gas. It is extremely inflammable, however, 

 which has led to its abandonment in many localities. Directions for 

 its use are given in Farmers' Bulletin 799 ^ " Carbon Disulphid as an 

 Insecticide." 



SUMMARY. 



1. The rice moth {Corcyra ce-'phalonica Staint.) has been known 

 to occur in the United States only since 1911, and was not identified 

 until 1916. 



2. Its origin is unknown, but it has been introduced at many points 

 in other continents and is as yet not strictly cosmopolitan. It has 

 been found commonly in England, where it was introduced in rice, 

 chiefly from India and Burma, and also in dried fruits. 



3. Its habit of feeding on cacao beans is probably an acquired one. 

 Evidently it is inclined to be omnivorous, since it breeds in rice, 

 dried fruits, the various products of cacao, such as cocoa, cacao 

 shells, and sweetened and unsweetened chocolate, ship biscuits, and 

 sesame seeds. It displays, however, no partiality for any of these 

 food substances. 



4. Its complete life history has not been traced, but, like other 

 indoor species, it reproduces nearly the year around under average 

 conditions. In the United States infestations appear to die down 

 from time to time, but are stimulated through new shipments of 

 cacao beans from South America and Central America. 



5. It produces copious and dense external webbing to which food 

 materials, such as rice, cocoa, and other matter, strongly adhere. 

 In this respect its work and injury resemble those of the fig moth 

 {Ephestia, cautella Walk.) and related species, and the Indian-meal 

 moth {Plodia interpimctella Hbn.). 



(6) While it has been recognized only from western Pennsylvania 

 and Porto Pico, it occurs without doubt at other points, and dealers 

 in rice, chocolate, and similar imported dry edibles should keep a 



1 The Farmers' Bulletins mentioned may be obtained free on application to the Division 

 of Publications, United States Department of Agriculture. 



