PLANTS USTSECTICIDAL PROPERTIES. 51 



Trilisa odoratissima (Walt.) Cass. Asteraceae. Carolina-vanilla. Eastern 

 United States. 



Jackson (43) states that the leaves are used to protect woolen 

 cloths from the attacks of moths. 



Triticum sp. Poaceae. Wheat. 



Scott, Abbott, and Dudley (83, p. 14) found wheat flour ineffective 

 against roaches, and Abbott (1, p. 7) found it of no value against 

 chicken lice, but McGregor and McDonough (59, p. 65) and others 

 have found it to be an insecticide against the red-spider, although 

 in this case it glues the mites fast to the foliage, thus causing death 

 mechanically rather than by poisoning them. 



Tropaeolum majus L. Geeaniaceae. Common nasturtium. Peru, culti- 

 vated in gardens. 



Von Mueller (91, p. 543) reports that it has some insecticidal 

 value, and it is even said that when planted around apple trees it 

 will rid them finally of the woolly aphis. 



Tssikoena. ( See footnote on page 26. ) 

 The writers' results are given on page 23. 



Tylophora fasciculata Ham. Asclepiadaceae. India. 



Greshoff (31, p. 108) reports that the leaves and roots are used 

 to destroy rats and other vermin. 



Umbellularia calif ornica (Hook. & Arn. ) Nutt. Latjraceae. Synonym: 

 Oreodaphne californica Nees. California-laurel. California to Puget Sound. 



Heamy (39) says that the tree is never attacked by insects, owing, 

 as it is supposed, to the volatile oil it contains. 



Chesnut (15, p. 531) says: "The leaves appear to be very valu- 

 able for driving fleas away." 



Veratrum album L. Liliaceae. White false-hellebore. White hellebore. 

 Europe and northern Asia. 



The powdered rhizomes and rootlets constitute the hellebore most 

 generally used as an insecticide. 



The writers' results are given on page 9. 



Veratrum californicum Durand. 



The writers' results are given on page 23. 



Veratrum nigrum L. Old World. 



Schreiber (80, 81) mentions this species and seems to think that 

 it is as good as V. album for insecticidal purposes. 



Veratrum viride Ait. Synonyms : Y. album viricle Baker, V. album Michx. 

 American hellebore. American false-hellebore. Green hellebore. North 

 America. 



Von Mueller (91, p. 556) says that it serves like other Veratrums 

 as an insecticide. 



Cook, Hutchison, and Scales (17, p. 17) say : " There are three 

 plants which are popularly called hellebore, namely, Veratrum 

 album, Veratrum viride, and HeUeborus niger. The term ' helle- 

 bore ' is correctly applied only to HeUeborus niger, which grows in 



