ECONOMIC ZOOLOGY ENTOMOLOGY. 553 



favor their development the psychodids may appear iu myriads at certain times 

 of the year and be carrie<l by the wind into inhabited neighborhoods so as to 

 give rise to an intolerable nuisance. 



The biology of the three pests named is dealt with. 



The grasshopper problem and alfalfa culture, F. M. Webstee {U. 8. Dept. 

 Affi'., Farmers' Bui. 637 {1915), pp. 10, figs. 8). — Three species of grasshoppers 

 are said to be largely responsible for the injury to alfalfa in the United States, 

 namely, the differential grasshopper {Mclanopliis diffcreniialis), the two-striped 

 grasshopper (.1/. bivittatufi), and 21. atlanis, a more or less migratory species. 

 Hardly a season passes without more or less serious outbreaks of these pests. 

 The publication consists largely of a popular account of them, their natural 

 enemies, and preventive and remedial measures. 



Thrips attacking' the leek (Thrips tabaci), A. Vuillet (Rev. Phytopath. 

 Appl., 1 {1913), No. 10, pp. 136, 137; ahs. in Rev. Appl. Ent., 2 (1914), 8er. A, 

 No. 5, pp. 278, 279).— In 1913 an attack by T. tahaci in the Department of Sarthe 

 resulted in a reduction of the Icvk crop I)y .50 per cent. 



Contribution to the knowledge of the sucking phenomena of plant lice and 

 the reaction of plant cells, F. Zweigelt (Centhl. Balct. [f'/c], 2. Alt., 42 (1914), 

 No. 10-1 4> pp. 265-335, pis. 2, figs. 7). — An anatomo-cytological study of plants 

 and coccids and aphidids. A bibliography of 65 titles is apijended. 



Phylloxera galls affecting pecan trees, E. S. Tuckeb (Louisiana Stas. Crop 

 Pest Notice 2 (1914), pp. 8, fig. 1). — ^This is a brief account of the occurrence 

 and nature of galls on pecan trees iu Louisiana caused by Phylloxera caryce- 

 caulis, P. (levastatrix, and P. perniciosa. 



The oak scale and its control (Lecanium quercifex), W. F. Turner (Ala- 

 bama Col. Sta. Circ. 28 (1914). PP- 105-110, fig. i).— The oak scale is the source 

 of considerable injury iu Alabama and the other Gulf States to oaks, several 

 species of which, particularly the water oak (Quercus nigra), are the principal 

 street and shade trees. The injury, while not confined to the young trees, is 

 much less apparent on the older ones. The pest is becoming more and more 

 abundant every year and constitutes a very serious problem in the care and 

 maintenance of shade trees. 



At Auburn, Ala., egg deposition commences early in April and continues for 

 about three weeks. Counts made of the eggs deposited by three females gave 

 2,245, 5,(X)0, and 5,262, respectively. The incubation period was found to be 

 about 26 days. The young are very active and may travel considerable distances 

 before settling, which occurs principally along the main or larger lateral veins 

 of the leaf. They may remain active for a considerable length of time even 

 after they reach the leaves. After settling they remain on the leaves until fall, 

 apparently remaining in the first stage throughout the summer. Migration to 

 the small twigs, where they remain dormant throughout the winter, takes place 

 the last of September. In February when the sap begins to flow growth com- 

 mences which continues until the last of March when it becomes very rapid 

 and. they soon attain their full adult size. 



The natural enemies of this species include two undetermined hymenopterous 

 parasites and several lady beetles of which Chilocorus oivulncrus is the most 

 important. Spraying experiments have shown Schnarr's insecticide 1 : 20 and 

 emulsions of Junior Red Engine and Diamond paraffin oils when applied in 

 March to kill about all of the scales with which they come in contact. The 

 emulsions are made by using 2 gal. of either oil to 1 gal. of whale oil soap and 

 50 gal. of water. 



The control of the moth borer, J. J. Quelch (Abs. in West India Com. Circ, 

 29 (1914), ^^0. 421, pp. 536, 537). — In this paper the author reports studies on 

 the control of the small moth borers (Diatrcea saccharalis and D. canclla). 



