PLANTS IXSECTK'IDAL PROPERTIES. 53 
Zanthoxylum clava-herculis L. Rit.ueae. Synonyms: 'A. carolmianum Lam., 
F agar a clava-herculis Small (U. S. P.), A. fraximfolium Walt., Z. tricarpum 
Michx. Prickly ash. Hercules-club. Southeastern United Sta1 
Riley (71. p. 185) reports that the powdered leaves seemed obnox- 
ious to cotton caterpillar-. 
Zea mays L. Poaceae. Indian corn. Maize 
Chittenden (76'. p. 8), quoting Brunei:, says that corn meal, dusl 
on cabbage plants in the morning while dew is on, causes the im- 
ported cabbage worm to drop off and thus it protects the plant- till 
washed off by the rain. 
Scott. Abbott, and Dudley (83. p. IS) found corn meal ineffective 
against roaches, and Abbott (1. p. 11) found cornstarch ineffective 
against the dog flea. 
Zygadenus venenosus S. Wats. Liliaceae. Zygadenus. Western Ui. 
States. 
The writer.-' results are given on page 24. 
GENERAL SUMMARY. 
Since 1915 the writers have determined that the following species 
of plants, when properly prepared and used, are efficient against 
certain species of insects: Quassia (Aeschrion exrfJsa). amianthium 
(Chrosperma muscaeto&icum) , pyrethrum or insect powder {Chry- 
santhemum cinerariaefolium), "cube," two species of derris (Derris 
eUiptica and uUginosa), common tobacco (Nicotiana tabacumj^sabB,- 
dilla (Schoenocaulon officinale), and white false-hellebore (Veratrum 
album). Other writer- report the following species of plants to be 
efficient against certain insects: Two species of Chrysanthemum (coc- 
cineum and marschaUU) , also used for making insect powder, clove- 
tree (CaryophyUus arorrvaticus) , Clavweps purpurea, "cucaracha" 
herb of Mexico (Haplophyton cimicidwm ). redcedar (Juniperus 
giniana) , and American false-hellebore (Veratrum viride). 
The writers found the following plants to have some insecticidal 
properties, but they proved to be inefficient against the insects used 
in the te-t- : Balbec. a Hondura- fish-poison, sandboxtree (H 
crepitans), margarita (Karwinshia humboldtiana) , common matri- 
mony-vine (Lycium haJimifolium). tomato {Ly coper si cum 
turn). Madhuca sp.. ehinaberry (Melia azedarach), moetoepoe, necoe- 
tae. Pangiwm eJhde, and common castor-bean (Ricinus comm\ 
Other writers report the following plants to have insecticidal proper- 
ties, but it is doubtful if any of them will prove efficient for pra< :< 
work: Aconite (Aconitum napelt/us), Aloe spp.. two species of 
Anthemis (cotannd tinctoria), butterflyweed {Asclepias tuberosa), 
pepper (Capsicum sp.), swallow-wort (Chelidonium majus), three 
species of Chrysanthemum (achitteae, mycoms, and p 
Cinchona succirubra } lark-pur (Delphiniwm sp.), black hellebore 
(HeUeborus niger), Jamaica fish-poison (Ichthyomethi la), 
henbane (Hyoscyamus rdger), German false-camomile 
chamomllla), Aztec tobacco {Nicotiana rustica), soapbai 
saponaria), lavender-cotton (Santolina chamat < ypa 
(Sassafras variifolium), and potato (Solanum tuberosum). 
