350 EXPERIMENT STATION RECORD. 



" The rate or velocity of insect development is affected by temperature, and, 

 other factors being constant, this rate increases in direct proportion to the in- 

 crease in temperature within the normal limits of development. The curve ex- 

 pressing the increase in rate of development is a true hyperbole. The Develop- 

 mental Zero, or what has been styled the ' critical point,' is at or near the point 

 where the reciprocal curve for the time factor intersects the temperature axis. 

 The thermal constant for an insect or any stage of an Insect is the constant for 

 the developmental curve for such insect or stage. The effective temperature 

 for conditions of variable temperature, 1. e., the ordinary daily variations, is 

 higher than the mean for the period. (This point is not supported by any evi- 

 dence in the present paper, but there is little doubt in the mind of the writer 

 that it will be found to be correct.)" 



The importance of the measure of evaporation in economic studies of 

 insects, V. E. Shelfoed {Jour. Econ. Ent., 7 (1914), No. 2, pp. 229-233) .—The 

 author reports upon a series of experiments conducted. 



The use of atmometers to measure evaporation in the study of insects, 

 V. E. Shelfoed {Jour. Econ. Ent., 7 {1914), -A^o- 2, p. 2^9). — A brief descriptive 

 account. 



Can insects become resistant to sprays? A. Lr. Melandeb {Jour. Econ. Ent., 

 7 {19U), No. 2, pp. 167-173).— The author states that the data at hand do not 

 permit the determination as to whether resistance and susceptibility are differ- 

 ences of degree and not of kind, or whether they behave as allelomorphs. 



Insecticides, L. E. Saybe {Trans. Kans. Acad. Sci., 26 {1912), pp. 138-141, 

 fig. 1). — The author's exi)eriments with cimicifuga, or bugbane, tend to show 

 that this drug has been greatly overestimated as to its toxic properties toward 

 insects. 



Powdered cimicifuga seems to be devoid of insecticidal properties, crickets 

 kept in contact with it for hours showing no ill effects. "As a fumigant cimi- 

 cifuga proved unsatisfactory, acting more as an anesthetic than as an insecti- 

 cide. One hundred times as much powdered cimicifuga as the amount of 

 sulphur that proved effective was used, or the fumes from 2 gm. of the drug in 

 a space of 9,000 cc. The insects were removed after a period of 1 hour, appar- 

 ently dead, but recovered after an hour or 2 hours' time." 



A commercial insecticide having the trade name " Vermingo," said to contain 

 6i per cent carbolic acid among other ingredients, as a fumigant had one- 

 fiftieth of the toxic power of sulphur, but by contact in an open jar it killed 

 almost instantly. 



Pyrethrum was tested as a fumigant but proved no superior to cimicifuga. 



Some properties of various forms of arsenate of lead, J. A. Dew {Jour. 

 Econ. Ent., 7 {1914), No. 2, pp. 162-167). — Experiments conducted with the plum 

 curculio in a peach orchard indicate that the killing power of arsenate of lead 

 varies directly with the percentage of AS2O5 that it contains. 



Notes on the entomology of the Arizona wild cotton, W. D. Pierce and 

 A. W. MoBRiLL {Proc. Ent. 80c. Wash., 16 {1914), No. 1, pp. 14-23).— The insect 

 enemies of TJturbcria thcs2yesioi(les observed by the authors include the boll 

 weevil Anthonomus grandis thurberice, accounts of which have been previously 

 noted (E. S. R., 30, p. 56) ; cotton leaf worm {Alabama argillacca) ; Thurberia 

 bollworm ; blister mites ; a leaf gall due to a species of Itonididje ; a mealy bug 

 {Pseiidococcus sp.) ; etc. 



Notes on the onion thrips and onion maggot, H. T. Febnald and A. I. 

 BouENE {Jour. Econ. Ent., 7 {1914), No. 2, pp. 196-200).— In the first part of 

 this paper the authors present a brief account of the life history and habits 

 of the onion thrips in Massachusetts, investigations of which have extended 

 over a period of about 5 years. 



