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NEW YORK STATE MUSEUM 



Control measures. Badly infested houses can be cleared of these 

 pests most easily l)y thorough and perhaps repeated fumigations 

 with hydrocyanic acid gas as described on page 42. Carbon 

 bisulrtd, has also been advised as a fumigant. On account of the 

 inflammability of the latter, \ve would prefer to use in houses the 

 somewhat more poisonous hydrocyanic acid gas. Carbon bisulfid 

 ■with its heavy fumes is particularly adapted to the destruction 

 of these pests in the holds of vessels. 



IP A still safer method of fumigation consists in burning pyrethrum 

 in infested compartments. It is stated that the vapors of this 

 insecticide are frequently more effective in destroying roaches 

 than the use of the powder itself. The room should be kept closed 

 from six to ten hours. The smoke of burning gunpowder is also 

 very obnoxious and deadly to roaches, particularly the black 

 English roach. The moistened powder should be molded into 



Fig. 21 Croton bug: a, fi.'c. d, successive stages in the development of the young; *, 

 adult; f, female, with egg case; g. egg case enlarged; h, adult, with wings spread; all 



natural s'ze except g. (After Riley) 



cones, placed in an empty fireplace and ignited. It is particularly- 

 valuable in the case of old houses. 



There are a number of roach poisons placed upon the market and 

 some of these are undoubtedly very efficacious, particularly if 

 assisted by persistent cleanliness and the eradication of inaccessible 

 haunts, so far as possible. We would further suggest the testing of 

 naphthalene in the flake form, as described on page 20, as a means 

 of at least partially suppressing this pest. The liberal use of Persian 

 insect powder or pyrethrum is also of service in destroying these 

 insects. The paralyzed cockroaches should be swept up and 

 burned. 



A relatively simple method, described by Mr Tepper of Aus- 

 tralia, is to mix plaster of paris one part, and flour three or four 



