1919] ECONOMIC ZOOLOGY ENTOMOLOGY. 353 



stems or pseudohulbs of cattleyas can be killed In the original eases with 

 hydrocyanic acid gas, provided a preliminary 20-in. vacuum is given." 



Experiments on cockroach control, E. V. Waltkb (Jour. Boon. Knt., 11 

 (1918), No. 5, pp. /.?/- 'i-'.'.i). — "Trajis may be used as means of control but can 

 not be relied on as a method of extermination. Boric acid Is a safe and 

 economical material to use against the- roaches as it is nonpolsonous to human 

 beings and yci very effective against roaches, a mixture of equal parts of pow- 

 dered borax and powdered sugar ground together is effective against cock- 

 roaches, is safe, and economical, although acting slower than boric acid. Cock- 

 roaches eat these substances in an effort to keep clean and not for any possible 

 food value." 



On a collection of Orthoptera (exclusive of the Locustidae) made in cen- 

 tral Peru by N. Iconnicoff and C. Schunke, A. N. Caudell (Insecutor Insottia 

 Uenatruus, 6 (1918), No. IS, pp. 70, pis. 2). 



Regarding Diapheromera veliei and Manomera blatchleyi, A. N. CATTOBU 

 (Ent. Ncics, 29 (1918), No. 7, pp. 258-260). 



Thysanoptera of Florida, J. R. Watson (Fla. Buggist, 1-2 (1918), No. !,-l, 

 pp. 53-55, 65-77). — The author lists 52 species known to occur in Florida and 

 gives keys for their separation. Franklmiella floridana from velvet beans at 

 Gainesville, Anthrotlirips dozicri from hop hornbeam (Ostrya virginiana), and 

 Cryptothrips citri on citrus at Frultland Park, Fla., are described as new. 



Notes on their distribution and host plants are included, and a bibliography 

 of 3G titles is appended. 



Additional data on the distribution and food plants of Lygus, with de- 

 scriptions of a new species and variety, H. H. Knight (Bui. Brooklyn Fat. 

 Soc, 13 (1918), No. 2, pp. ^2-^5, fig. 1). — This paper presents notes on the distri- 

 bution and food plants of species of Lygus not included in the previous paper 

 (B. S. R., 38, p. 461), and describes two forms new to science, namely, Lygus 

 (Neolygua) nyssce taken on sour-gum (Nyssa sp.) at Auburn and Le Roy, Ala., 

 and L. tiliCB hcterophyUits from Tilia heterophylla in Florida, Georgia, and 

 Mississippi. 



An outbreak of the cotton stainer on citrus, J. It. Watson (Fla. Buygist, 

 2 (1918), No. 2, pp. 88-90; Flo. Grower, 18 (1918), No. 25, p. 9).— The author 

 reports that citrus and avocado growers in some of the southern counties of 

 Florida, where in order to escape the boll weevil cotton was raised in 191S, have 

 had trouble with the cotton stainer. It punctures the rind of citrus and the 

 fruit then drops from the tree and decays. The author concludes that cotton 

 growing in citrus communities should be abandoned. 



An extra molt in the nymphal stages of the chinch bug, H. Yuasa (Ent. 

 Neics, 29 (1918), No. 6, pp. 233, 23' f ).— In work at the Kansas Experiment Sta- 

 tion, the author has found an extra or fifth stage of the chinch bug to occur 

 between either the first and second or second and third stages as described by 

 Riley. 



Leaf burn of the potato and its relation to the potato leaf-hopper, E. D. 

 Ball (Science, n. set:, 48 (1918), No. 1834, p. IP'/). — There has been a remark- 

 able epidemic of leaf burn on potatoes throughout the northern section of the 

 United States, from Montana to New York and south at least to Iowa and 

 Ohio. "The margins of the leaves of early varieties turned brown, the dead 

 areas gradually widening until the leaves dried up and the whole field took on 

 a burned appearance. In severe cases the stalks also withered and died." 



In the potato sections of Wisconsin, all of which were affected, a careful 

 study by the author showed that in every case the injury was directly pro- 

 portioned to the number of apple leaf-hoppers present. In cage experiments 



