ECONOMIC ZOOLOGY ENTOMOLOGY. 253 



insecticides stucli fast iu exudations on portions of the insect body, wliere they 

 became partly dissolved, after wliich they appeared to be slowly absorbed 

 tbrougti tlie body integument. 



" Both powdered borax and sodium fluorid may kill cockroaches in the man- 

 ner of purely contact agents, but normally they become stomach poisons as 

 well — since the roaches regularly lick and swallow some of the powder in clean- 

 ing it from their bodies. • 



" In tlie case of powdered solid contact insecticides, the advantage seemed 

 to lie in having the powder so fine and dry that it could sift readily into all 

 crevices and could adhere well. Similarly, other things being equal, a weak 

 surface tension gave a liquid contact insecticide an advantage, enabling it to 

 thoroughly wet the bodies of insects and to flow into all irregularities of the 

 area treated. 



"Among several substances which were found to increase the ' spread ' of lime- 

 sulphur solution, saponin or extracts taken directly from the stems and leaves 

 of Saponaria officinalis (bouncing bet) seemed to be best. It is suggested that 

 perhaps the use of extracts from ' bouncing-bet hay ' with lime-sulphur solution 

 might prove profitable in orchard spray practice. 



"Experiments with ammonia (derived from dry liquefied ammonia) as a 

 fumigant for mill insects were rather disappointing, but the liquefied ammonia 

 was easy to apply and might prove to be a desirable fumigant for insects in some 

 instances. 



" When carbon tetrachlorid was compared with carbon disulphid as to its 

 action on grain insects in tight flasks, six times as much of the former was 

 required for effective fumigation. The carbon tetrachlorid was vaporized with 

 heat and satisfactorily used at the rate of 3.55 lbs. for 100 cu. ft. of air space, 

 to insure furs against moths — fumigation being repeated every five weeks during 

 the summer months. The charge as used killed adults of Tinea Mselliella. 



" Evidence indicates that heat might be applied to advantage as an insecticide 

 in many situations where it has never been the practice to use it." 



Winter cover washes, A. H. Lees {Ann. Appl. Biol., 1 (1015), No. S-4, pp. 

 S51-364 ) . — The experiments here reported were conducted with a view to obtain- 

 ing more definite information on psylla control, experience having shown that 

 a lime wash applied as late as possible before the buds burst in the spring will 

 cause a very decided decrease in their attack. 



The results indicate that " a thick covering largely prevented the appearance 

 of larvse in the buds. The lime coatings largely prevented rupture of the egg- 

 shell, and where rupture had taken place many had not succeeded in getting out 

 of the shell. Of those that had, many did not succeed in getting to the surface. 

 Of those that had succeeded in getting to the surface, a good proportion were 

 killed by the powdery lime adhering to their bodies. The whiting coat almost 

 entirely prevented hatching, but did not have such a desiccating action. Under 

 laboratorj^ conditions a thin wash as lime and water 1 : 10 produced as good a 

 result as a thick wash, but under outside conditions a thick coat is necessary in 

 order to allow for the eroding power of weather conditions." Thus it appears 

 that the beneficial action of lime wash on psylla eggs is due to the mechanical, 

 sealing action rather than to any chemical effect. 



Correction of the misuse of the g'eneric name Musca, with, description of 

 two new genera, C. H. T. Townsend {Jour. Wash. Acad. Sci., 5 {1915), No. 12, 

 pp. 433-4S6). — The genera Promusca of which Musca domestica is the genotype 

 and Vivipart)musca of which if. bczzi is the genotype are erected. It is pointed 

 out that M. vomitoria was designated by Latreille in 1810 as the type of the 

 genus Musca. 



22434°— No. 3—16 5 



