19-0] ECONOMIC ZOOLOGY — ENTOMOLOGY. 353 



atioii of iiisoct jiowdcr \\Iii<li have been hugely practioed, imicli to the 

 detriment of the industry, have led to the invest Ijiation.s here reported, made 

 witli a view t<> devising: metliod.s for the quantitative determination of sueh 

 adulteration and for determininfj the reasonable aliowanees in the amounts of 

 stems and acid-insoIul)le ash in insect powder. It is pointed out that tlie addi- 

 tion of the powdered stems of the plant has been the most serious form of 

 adulteration practice, in some cases having been carried to the extent of com- 

 plete substitution. The data presented, much of which is in tabular form, 

 have been sunnnarized by the authors as follows : 



" The fact that flowers of certain species of Pyrethrum possess the property 

 of Eilliiig various insects was known to the people of eastern Europe more 

 than a century a^o. Since that time this knowledge has gradually spread 

 until insect i)owder is now a common household convenience. The powder 

 owes its insecticidal activity to a mixture of acids and esters which first be- 

 numb and subsequently kill the insects brought into contact with it. While 

 It is generally considered to be harmless to the higher animals, a number of 

 cases where it has produced symptoms of a more or less serious nature are 

 record etl. 



" At present insect flowers are cultivated commercially in Dalmatia, Japan, 

 Australia, Algeria, and California in the United States, the first three countries 

 producing nearly all of the flowers that enter into international trade. The 

 powder is made in each of these countries. 



" In the enforcement of the Insecticide Act, insect powder has been found 

 adulterated in a variety of ways. In some instances such substances as lead 

 chromate, curcuma, and yellow ocher are added to give color. Other species 

 of flowers, like the Hungarian or oxeye daisy, are substituted in whole or in 

 part for the true insect flower, while almond shells, brick dust, hellebore, 

 pepper, sawdust, starch, sumac, and the like have been found less frequently 

 in samples examined. The gi'ound stems of the Pyrethrum plant, however, 

 probably constitute over 95 per cent of the adulterants used in insect powder 

 at this time. 



" Physiological, chemical, and microscopical methods which can be used satis- 

 factorily in detecting adulteration with powdered stems have not as yet been 

 perfected to such a degree as to make an accurate quantitative determination 

 jtossible. However, from the data obtained in the examination of luindreds of 

 samples of genuine insect powder, of the materials used for its sojihistication, 

 and of commercial samples, the results «>f which are reported in this bulletin, 

 a formula given here has been developed by which it is possible to determine 

 In an insect powder the approximate amount of added Pyrethrum stems 

 present." 



A bil)liography of 209 titles is appended. 



Poison baits for grasshoppers, W. P. Flint (Jour. Econ. Ent., 13 (1920), 

 Jio. 2, pp. 232-231). — This is a brief report of work with poison baits in Illinois, 

 where at least 75 per cent of the damage by grasshoppers occurs in fields of 

 clover, alfalfa, soy beans, cowpeas, and other legumes. 



Since legumes are distinctly attractive to grasshoppers, experiments were 

 made with poison baits having a distinct legume odor. In experiments in which 

 use was made of the inner bark of the black locust (Robinia pseudacacia) . 

 which possesses the strongest characteristic legume odor to be found in any 

 plant, nearly as many grasshoppers were killed where it was used as with the 

 molasses and lemons. A comparison made in 191S and 1919 of the standard 

 bran mash with the same amount of bran and Paris green mixed with water 

 containing 3 lbs. of linely-ground green beans gave an average of 2 dead grass- 

 hoppers per square yard more in the areas treated with green beans. In tests in 



