198 



A temperature of 50° C. (122° F.) kills the larvae in three hours 

 and the eggs in five. In practice it is possible to kill L. serricorne, even 

 in the centre of a bale, by heating the latter in a fermentation room 

 to a temperature of 55°-60° C. (13r-140° F.). The tobacco is not 

 injured. This method is practicable on all estates that have a 

 fermenting room. 



It was found that a dose of \\ litre benzine per cubic metre (about 

 2 pints per cubic yard), allowed to act over a consecutive period of 

 96 hours, is sufficient to kill all stages of L. serricorne , even at the centre 

 of a bale. In normal times, however, disinfection with benzine will 

 be more expensive than with carbon bisulphide. 



Weiss (H. B.). Notes on the Life-history o8 Pachypsylla celtidis- 

 gemma. Riley. — Canad. Ent., London, Out., liii, no. 1, January 

 1921, pp. 19-21. 



The nymphs of Pachypsylla celtidis-genima, Riley, a species locally 

 common in New Jersey, form galls on the twigs of hackberry {Celtis 

 occidentalis) . The galls are always formed on the new wood, and in 

 severe infestations almost every bud is deformed. P. celtidis-gemma 

 hibernates in the last nymphal stage, these nymphs emerging from the 

 galls late in May and early in June. They crawl on to the tops of the 

 galls and to the twigs, and give rise to the adults shortly afterwards. 

 The eggs are deposited on the lower leaf-surface close to a vein. First- 

 stage nymphs were not found on the buds until July. Brief descriptions 

 of the development of the nymphs and of the egg are given. 



LocHHEAD (W.). The Natural Control of Insects. — 12th Ann. Kept.. 

 Quebec Soc. Prot. Plants Insects & Fung. Dis., 1919-20, Quebec, 

 1920, pp. 10-21, 5 figs. [Received 21st February 1921.] 



The importance of the natural control of insect pests, including 

 climate, food supply, predatory enemies and parasites, and the 

 necessity for further knowledge of these conditions, is emphasised. 



Chapais (J. C). A Brief Study of a few Ceeidomyiidae. — 72/// Ann. 

 Kept. Quebec Soc. Prot. Plants Insects & Fung. Dis., 1919-20, 

 Quebec, 1920, pp. 28-31, 1 fig. [Received 21st February 1921.] 



The information here given on the Cecidomyiids, Mayetiola destructor. 

 Say, Perrisia {Dasyneiira) leguminicola, Lintn. (clover flower midge), 

 Neocerata {D.) rhodophaga, Coq. (rose midge) and Contarinia vir- 

 giniana producing galls on choke cherry {Cerasus virginiana), has been 

 collated from various sources. 



LocHHEAD (W.). The European Corn Borer. — 12th Ann. Kept. 

 Quebec Soc. Prot. Plants Insects & Fung. Dis., 1919-20, Quebec, 

 1920, pp. 36-43, 2 plates, 1 fig. [Received 21st February 1921.] 



The proceedings of conferences on the European corn borer 

 [Pyrausla nubilalis, Hb.] are reviewed ; the bulk of the information 

 has already been noticed [R. A.E., A., viii, 97^ etc.] 



