Mar. 4. 1918 Toxicity of Organic Compounds to Insect Eggs 



581 



chemically, such as allyl alcohol, which contained ammonia as an im- 

 purity, and chlorpicrin. In general those sprayed showed a higher 

 percentage of hatching than those dipped. Some compounds of this 

 series, the vapor of which had been previously shown (6) to be non- 

 toxic to houseflies, owing to the fact that they formed gummy masses 

 on exposure to the air, were found to be toxic to the insect eggs. Pinene, 

 terpineol, and geranyl acetate are examples of such chemicals. Kurther, 

 it is noted that compounds which are so slightly volatile, owing to 

 their high boiling point, that they were ineffective against flies, were 

 found to be toxic to the insect eggs. Such chemicals were eugenol, 

 alpha naphthol, ethyl ether, and trimethylene cyanid. These com- 

 pounds are only effective, however, when brought into actual contact 

 with the eggs, as in spraying or dipping, and are no more effective as a 

 fumigant against the eggs than they are against adult insects. 



Table I. — Relation of the boiling point to the toxicity of organic compounds used in 

 dips and sprays for potato-beetle eggs 



Organic compound. 



Ethyl ether 



Ethyl mercaptan . . . 

 Carbon bisulphid . . . 

 Petroleum ether . . . . 



Acetone 



Chloroform 



Methyl alcohol 



Carbon tetrachlorid . 



Ethyl alcohol 



Gasoline 



Benzene 



Thiophene 



Allyl alcohol 



Amyl nitrite 



Nitromethane 



Propyl acetate 



Toluene 



Chlorpicrin 



Pyridin 



Acetic acid 



Chlorbenzene 



Amyl alcohol 



Xylene 



Amyl acetate 



Bromoform 



Pinene 



Ethyl malonate 



Allyl isosulphocyan 



ate 



Furfural 



Butyric acid 



"C. 



35 



36.2 

 46 

 40-70 



56-3 

 61 



66. s 

 78.1 

 78.4 

 70-90 

 80.3 

 84 



97 

 98 



lOI 



IC2 



III 



112 



116. 7 



119 



132 



137 



140 



148 



151. 2 



160 



160 



161 

 162 

 163 



O v. 



2-oS 



g bio 



100 

 97 



95 

 85 



100 



44 

 100 

 100 



.S-d 

 •S >. 



CO u 



100 

 ICO 



100 



100 

 100 



ICO 



100 

 100 



Organic compound. 



Trimethylene bromid 



Terpineol 



Benzonitrile 



Thiophenol 



Benzaldeliyde 



Anilin 



Ortho-bromtoluene . . . 



Valeric acid 



Ortho-creosol 



lodobenzene 



Salicylic aldehyde. . . 



Para-cresol 



Meta-cresol 



Nitrobenzene 



Benzyl alcohol 



Kerosene 



Ortho-nitrotuluene. .. 



Bromxylene 



Citral 



Quinolin 



Eugenol 



Nitroxylene 



Nicotine 



a-Napthol ethyl 



ether 



Trimethylene cyanid 



Geranyl acetate 



Brbmmethylphenyl- 



ketone 



Ethyl aceto-acetate. . 



°C. 

 165 

 168 

 170 



172.5 

 179. I 

 182 

 182 



184.5 

 190 



193 

 196 

 201.8 

 202. 8 

 205 

 206. 5 

 150-300 

 223 

 225 

 225 

 239 

 247-5 

 250 



274 



Si 



»- . 



i >. 



bt'2'3 



.a c3 ce 



C4 O H 



01 o. n 

 M-- — 



Ssfa 



17 



