1917J ECONOMIC ZOOLOGY ENTOMOLOGY. 559 



trematode the larva of which was found to infest a crab (H, tridens) in Japan. 

 Of some 250 specimens of crabs examined 90 per cent were found to be infested 

 with cysts of this parasite. Though this crab is not used as food in Japan 

 proper, it is said to be eaten in some parts of Korea and Formosa. 



The death-feigning instinct, E. M. DuPobte {Canad. Ent., 49 (1917), No. 7, 

 pp. 221-225). — Tlie author concludes that there is no consciousness involved in 

 the death feint and that the instinct is merely a physicochemical reaction to 

 external stimulus. " The most probable theory is that in the death feint we 

 have an example of negative thigmotaxis, that shrinking from contact charac- 

 teristic of so large a proportion of all classes of animals." 



Arsenic as an insecticide, A. L. Lovett and R. H. Robinson {Jour. Econ. 

 Ent., 10 {1911), No. S, pp. SJf5-S49). — A brief report of experiments conducted 

 in which lampblack and fullers' earth were used as adsorbents of arsenic from 

 a water solution of arsenic acid. 



It was found that under field conditions lampblack is not practical as the 

 black color probably absorbs heat and increases the burn. Fullers' earth used 

 as an adsorbent gave comparatively little burn. The results, based on a single 

 Beason's observations, both as to toxicity for insects and as to amount of burn 

 on apple foliage, indicate that there are possibilities in the use of adsorbents 

 with arsenic. 



Toxicity of various benzene derivatives to insects, W. Moose {U. S. Dept. 

 Apr., Jour. Agr. Research, 9 {1917), No. 11, pp. 371-S81, pis. 2, figs. 2).— In con- 

 tinuation of fumigation work for the destruction of external parasites, previ- 

 ously reported (E. S. R., 35, p. 656), the author reports upon a series of 28 

 benzene derivatives. The results obtained, at the University of Minnesota, are 

 summarized as follows : 



" All the benzene derivatives tested proved to be more toxic to insects, mole- 

 cule for molecule, than carbon bisulphid. Physical characters, such as boiling 

 point and vapor pressure, have more influence on the toxicity than chemical 

 composition. Up to 250° C. the higher the boiling point the more toxic the 

 compound to insects. Beyond 250° the compound is usually so slightly volatile 

 that not enough of the chemical will evaporate to be effective. Lipoids are very 

 soluble in compounds with low boiling points and but slightly soluble in com- 

 pounds with high boiling points. Compounds with low boiling points, although 

 less toxic, owing to their great volatility may give better results than com- 

 pounds with high boiling points, particularly in the fumigation of grain." 



Carbon disulphid as an insecticide, W. E. Hinds {U. S. Dept. Agr., Farmers' 

 Bui. 799 {1917), pp. 21). — This is a revision of Farmers' Bulletin 145, previously 

 noted (E. S. R., 13, p. 971). 



Nicotin sulphate as a poison for insects, A. L. Lovett {Jour. Econ. Ent., 

 10 {1917), No. 3, pp. 333-S37). — The author's experiments with Malacosoma 

 pluvialis indicate that nicotin sulphate is a very powerful repellent for cater- 

 pillars. Where feeding does take place, the action of the nicotin is apparently 

 rapid and sure, even small bits of foliage sprayed with comparatively weak 

 solutions killing, when devoured, after a short time. 



Tests of nicotin sulphate in the control of the codling moth made under 

 unfavorable conditions are briefly considered. 



The practical use of the insect enemies of injurious insects, L. O. Howabd 

 (17. S. Dept. Agr. Yearbook 1916, pp. 273-288, figs. 8).— A brief popular account 

 in which attention is called to the beueflts obtained from the use of insect 

 parasites and predators. A technical account of some of the work has been 

 previously noted (E. S. R., 25, p. 662). 



Losses caused by imported tree and plant pests, C. L. Mablatt {Amer. 

 Forestry, 23 {1917), No. 278, pp. 75-80, figs. 12).— A. discussion of the losses re- 



