83 



Watson (J. R.). New Thysanoptera from New York.— B////. Brooklyn 

 Enf. Soc, xvi, no. 3-4, June-October 1921, pp. 78-86. 



Tlie following new species are described : Trichothrips drakei, 

 taken from Phylloxera galls on hickory and under the bark of black 

 locust trees ; T. salicis, on willow ; Cryptothrips adirondacks, on 

 willow and Viburnum alnifolitim; and Idolothrips fuscus, collected 

 from old burrows of a Cerambycid in a basswood twig. 



Sherwood (A. H.). U.S. Bur. Ent. Poisoned Bait as a Control for 



Grasshoppers. — 5. Dakota Slate Coll. Agric. & Mecli. Arts., 



Brookings, Extens. Circ. 5, June 1918, 8 pp., 4 figs. [Received 

 9th December 1921.] 



The measures that have been found most successful against grass- 

 hoppers in South Dakota, where the damage has been considerable 

 during the last few years, are the use of poisoned bait, hopperdozers, 

 spraying, and the assistance of poultry and pigs. The present circular 

 gives Severin's formula [R.A.E., A, v, 382] and instructions for the 

 use of poisoned bait. 



Craighead (F. C). Hopkins' Host-selection Principle as related to 

 certain Cerambycid Beetles. — Jl. Agric. Res., Washington, D.C., 

 xxii, no. 4, 22nd October 1921, >p. 189-220. 



With a view to securing further evidence relating to Hopkins' host- 

 selection principle [R. A.E., A, v, 210], the experiments here described 

 were begun in 1914. The principle, as defined by Dr. Hopkins, is that 

 " a species which breeds in two or more hosts will prefer to continue 

 to breed in the host to which it has become adapted." Problems 

 gradually arose demanding a broadening of the investigation until 

 in 1918 over 100 individual experiments were in progress. Fourteen 

 species of insects and 21 species of plants were used, involving the 

 formation of 45 host strains. Investigations are still in progress, and 

 several points still remain to be conclusively settled, but sufficient 

 data have been collected to show definitely to what extent the influence 

 of the food-plant apphes to these insects. The references of previous 

 authors to this principle are briefly reviewed, and the technique 

 employed during the present observations is described. 



The beetles used were Xylotrechus colomts, F., Cyllene piclits, Dru., 

 C. crinicornis, Chev., Callidiumantennatuni, Newm., Cjanthinum, Lee, 

 Hylotrupes ligneus, F., Neoclytus capraea, Say, A^ erythroccphahts, F., 

 Molorchus bimaculatus, Say, Liopus alpha, Sa}', and Hyperplalys 

 maciilatus, Hald. 



The following is part of the author's summary of the results of these 

 experiments. In practically all species experimented with, the adults 

 show a marked predilection for the food-plant in which they have fed as 

 larvae, provided that they are not deterred by other factors, such as the 

 unfavourable condition or the small quantity of the food-plant. There 

 is considerable variation in the degree of preference for the original 

 food-plant, as between different species. In forced transference of 

 individual adults of a species to a new food-plant, a high mortality 



