- 126 - 
1936 Boyce, 38 
1936 Federated Malay States, 142 
1936 Nihon Nohyaku Go . , 309 
1937 Wheatley, 462 
1937 Hill, 194 ■ 
1937 Tisdale, 407 
1937 Killip, 242 
Dietz of the DuPont Company (116) in 1938 discussed the use of 
plant extractives in insect control. Mention is made of Derris, 
^onchocarpus, Tephrosia, Pyr^thrum, etc. Although a search for irtsecti- 
cidally active plant extractives other than those now known is admittedly 
a fascinating problem, it is one on which a tremendous amount of effort 
can be spent without yielding any immediate, highly practical t profitable 
results. 
A review of recent progress in stomach poison insecticides, derris, 
cube, pyre thrum, etc., by an anonymous writer (6) appears in the 2"ews 
Edition of Industrial and Engineering Chemistry for January 10, 1938. 
Work with derris and cube for the control of the Mexican bean 
beetle, the pea aphid, and other pests by State and Federal entomologists 
is reviewed 'oy the National Canners Association, "Bureau of • Raw Products 
Research, C. G. Woodbury, director (298), in a bulletin issued in January, 
1938. 
The United States 'Bureau of Entomology and Plant Quarantine has 
called attention to the comparison by Roark (353) of cube and derris; 
and to the procedure of Jones and Graham (226) for the determination of 
rotenone in derris and cube by extraction with chloroform. 
Sievers et al. (373), in their study of Forth American species of 
Tephrosia as commercial sources of insecticides, refer to Jones, Campbell 
and Sullivan (225), who pointed out that the rotenone content of samples 
of native species of Tephrosia examined by them are not on a par with 
that of derris ( Perris sp.) and cube ( Lonchocarpus nicou (Aubl.) DC.) 
now available, but suggest that more toxic individuals of these species 
may be found and that the rotenone content may perhaps be increased by 
selection,- breeding, and cultivation. 
D. W. Smith (380,381), of the United States Department of Commerce, 
Bureau of Foreign and Domestic Commerce',' has called attention to the 
report by Spoon (389). 
ACKNOWLEDGMENT 
The manuscript of this publication was read by the following, who 
contributed helpful suggestions: D. L. Van Dine, principal entomologist, 
in charge, Fruit Insect Investigations; W. H. White, principal entomologist, 
in charge, Truck Crop and Garden Insect Investigations; R. W. Earned, 
principal entomologist, in charge, Cotton Insect Investigations; F. C. Bishopp, 
