47 



has also been recorded on potatoes, tomatos, beans, beets, squash, 

 pumpkin, maize, plum trees and even poplars. 



Reinhard (H. }.). Peach Seedhngs attacked by Dipterous Larvae.— 



Jl. Econ. Ent., Geneva, N. Y., xiv, no. 3, June 1921, pp. 305-306, 

 [Received 22nd November 1921.] 



Hylemyia cilicrura, Rond. {Phorbia fusciceps, Zett., of authors), 

 is recorded as infesting peach seedlings in Texas. This fly is 

 considered by Howard to be identical with Anthomyia zeae, Riley 

 (seed corn maggot). 



Graha:^! (S. a.). Subcortical Temperature of Logs exposed to direct 

 Sunlight.—//. Econ. Ent., Geneva, N.Y., xiv, no. 3, June 1921, 

 pp. 307-308. [Received 22nd November 1921.] 



From work conducted at the Minnesota Experiment Station the 

 author has reached conclusions similar to those of Craighead [R. A.E., 

 A, viii, 365] so far as some species of logs are concerned. These 

 experiments have also shown that, in northern latitudes at least, 

 even on the brightest days some logs never reach a temperature fatal 

 to insects. A summary of the results so far obtained is given here, 

 details of which have been published elsewhere [R.A.E., A, ix, 437]. 



In bright sunlight the subcortical temperature on the upper side of 

 moderately thin barked logs often passes above a point fatal to insects, 

 but this is^ not true of all logs, as thin barked Norway pine logs never 

 exceeded a temperature of 46° C. during the summer of 1920. Solar 

 radiation is one of the chief factors influencing the temperature. In 

 the absence of solar radiation the subcortical temperature follows that 

 of the surrounding air rather closely. The conduction of heat around 

 a log is slow, but varies with different species, resulting in concentra- 

 tion of heat in limited areas. Movement of air tends to increase 

 radiation and reduces thereby the subcortical temperature. The 

 temperature is also lowered by the evaporation of water, as occurring 

 in the morning or after rain from the surface layers of the bark. Close 

 proximity to other radiating or absorbing surfaces tends to stabilise 

 subcortical temperature. 



Symes (C. B.) & Chorley (J. K.). Insect Pests oJ Mushrooms.— 



Emit Grower, Fndterer, Florist & Mkt. Gdnr., London, li, no. 1313, 

 27th January 1921, pp. 142-145; no. 1314, 3rd February 1921, 

 pp. 188-190; no. 1315, 10th February 1921, pp. 234-236; 

 no. 1319, 10th March 1921, pp. 454-456 ; no. 1320, 17th March 

 1921, pp. 494-496. 7 plates, 23 figs. [Received 24th November 

 1921.] 



Sciara praecox, Meig. (mushroom fly), which is frequently beneficial 

 in causing early putrefaction and decay of the fungi attacking British 

 trees, is the worst pest of mushrooms in Britain, sometimes completely 

 ruining the crop. Its life-history varies greatly, according^ to the 

 temperature or humidity of the mushroom house ; in the field the 

 pest is almost negligible. The eggs are laid in strings or batches of 

 9 to 12, or sometimes singly, either at the base of the mushroom, 

 at the junction of stem and cap, between the gills, or in the angle 

 between two adjacent stems converging at the base. An average of 

 30-35 eggs is laid by each female ; the incubating period is 5 or 6 

 days at warm temperatures. The larva, which moults three times. 



