554 EXPERIMENT STATION RECORD. [Vol. 41 



" G. affinis is especially suitable for antiruosquito work because (a) it seeks 

 its food at the surface, (b) it is very prolifie, (c) it gives birth to well- 

 developed young, therefore requiring no special environment for depositing and 

 hatching the eggs, (d) it lives and thrives under a large variety of conditions 

 and frequents areas especially suitable for the support of mosquito larvae, [and] 

 (e) it usually lives and multiplies in ponds stocked with predacious fishes, 

 providing it has very shallow water for refuge." 



The comparative effectiveness of certain culicifuges under laboratory con- 

 ditions, A. Bacot and G. Talbot {Parasitology, 11 (1919), No. 2, pp. 221-236, 

 fig. 1). — A detailed report of investigations of the comparative efficiency of 

 culicifuges conducted for the British War Office. 



"For the purpose of testing culicifuges, numbers of Stegomyia fascmta (the 

 yellow fever mosquito) bred in incubators were placed in cages kept in the 

 laboratory. The effici^ency of the preparations was tested by coating the fore- 

 arm with a definite quantity of one or other of them and exposing in a cage, 

 each test being controlled by inserting after a short interval the other and un- 

 treated arm in the same cage, the number of bites being compared in each 

 case. By this procedure it was hoped to obtain a measure of the relative pro- 

 tection which the culicifuges might be expected to afford when used under 

 practical conditions against Anopheles mosquitoes. 



" In the first series of trials, conducted within 15 minutes of application, 8 

 preparations out of a total of 22 tested gave satisfactory results. Their active 

 ingredients were (1) oil of cassia and camphor, (2a) oil of cassia and pepper- 

 mint, (5) oil of eucalyptus and citronella with phenol, (9a) crude naphthalin 

 (coke oven) and camphor, (10) crude ' Parasitox,' (15a) light wood oil, (21) 

 oil of turpentine, (22a) ' Lawson's Anti-mosquito Compound.' These prepara- 

 tions were then tested to ascertain for what period their protection could be 

 depended upon. Preliminary trials indicated that this period was not likely to 

 extend for more than two hours between treatment of the arm and exposure in 

 the cage. None of the preparations gave complete protection in this series of 

 trials." 



The tobacco flea-beetle, Z. P. Metcalf and G. W, Underhill (North Carolina 

 Sta. Bui. 239 (1919), pp. 47, figs. 3^).— A detailed report of studies of the 

 biology and control of the tobacco flea-beetle (Epitrix parvula), the most im- 

 portant insect enemy of tobacco occurring in North Carolina. 



The adult is the source of mbst of the injury to tobacco, this injury being 

 characterized by small, round, or irregular feeding punctures scattered over 

 the leaf surface or by a more or less complete skeletonization of the leaf. It 

 was found that a beetle consumes an average of 10.3 times its own weight per 

 day. 



The species, which apparently occur in the United States wherever tobacco 

 is grown, is rather widely distributed in the tropical and temperate regions of 

 the world. It feeds by preference on any and all of the members of the Solan- 

 acese. The adults, in which stage the winter is passed, emerge early in the 

 spring and the damage which they cause to tobacco beds is itsually very ex- 

 tensive. The eggs are laid from April to September, on or very near the sur- 

 face of the ground immediately under the host plant at an average rate of 2.21 

 per day for a period of, assumed as, at least 90 days. They hatch in from 

 6 to 8 days in midsummer. In a study of the larvie in the field they were 

 found to feed upon the roots of the plants of the solanaceous family, none 

 ever being found feeding upon the leaves. In special cases it was found that 

 they not only feed upon but often tunnel the stalks of tobacco and ground 

 cherry plants for a distance of several inches. In the field they were normally 



