- 33 - 
la': le 1. — Clas3ified list of insects against wh^ch derris has been tested 
Reference 
Insect and Stage 
Crthoptera 
Blattidae 
Preparation 
Effectiveness 
Blattella germarica L. Powder + tobacco Effective 
(G-erman cockroach) dust (1+4) as a 
dust 
Ditto 
Ditto 
Pov/der + tobacco Effective 
dust (1+4) + 
flour and sugar 
as a bait 
Powder as a dust 57.5% kill in 
1 week 
Periplaneta americana Powder + tobacco 
L. (American cockroach) dust (1+4) as a 
dust 
Effective 
tiilmer (44) in 
1923 
Ditto 
LIcIndoo, 
Si overs, and 
Abbott (S6) 
in 1919 
Gilmer (44) in 
1923 
Ditto 
Powder + tobacco 
dust (1+4) + 
flour + sugar as 
a poison bait 
Effective 
Ditto 
Gryllidae 
Gryllotalpa sp. 
(i.iole cricket) 
Extract 
Ditto 
Ditto 
Powdor in v/ater 
(1:531) 
Uncertain 
Mallop haga 
Mallophaga on chickers Powder as a dust Effecti'/e 
Powder as a dust Effecti-e 
Effecti-'re 
Federated Malay 
States Dept, 
Agr. (28) in 
1920 
Mclndoo, 
Si e vers, and 
Abbott (36) in 
1919 
Wells, 3isjiopp, 
and Laako (109) 
in 1922 
Ditto 
