208 



there is a very great danger of their early migration from the western 

 side of the Cauca River. The cUmatic and topographical conditions 

 likely to lead to such an invasion are discussed. There is a fairl}' 

 general opinion, which the author shares, that locust invasions die out 

 less by reason of the artificial methods employed than as a result 

 of a period of heavy rain. It is known that the insects remain within 

 certain definite zones for a period of years, and only occasionally 

 descend in large swarms into the valleys to the north and south of 

 Colombia. In the author's opinion, it is the rain barrier that exists 

 in the hilly regions all around the locust zones that keeps the insects 

 confined within them. During exceptionally long periods of drought, 

 however, even this barrier region may become dry, and then the 

 locusts will migrate to the valleys, where they find cultivated crops for 

 food and dry conditions favourable to their multiplication. This theory 

 is based entirely upon the influence of rain upon the insects, of which 

 the author has made a personal study. If the theory be true, the 

 obvious remedy is to send a Commission to locate the breeding places, 

 and as an invasion seems to be imminent, work on these lines should 

 be promptly undertaken. 



Verwendung von Arsenpraparaten gegen Obstbaumschadlinge. [The 

 Use of Arsenicals against Fruit-tree Pests.] — Schweiz. Zeitschr. 

 Obst- u. Weinbau, Frauenfeld, xxx, no. 4, 19th February 1921, 

 pp. 52-56. 



Arsenicals have only recently come into more or less general use 

 as insectides on the Continent. In France such insoluble preparations 

 as lead arsenate, Paris green, etc., have been permitted by law since 

 1916, but soluble compounds are prohibited. This article, intended 

 for Swiss orchardists, describes the spraying methods usual with 

 arsenicals. 



Jaarboek van het Departement van Landbouw, Nijverheid en Handel 

 in Nederlandsch-Indie 1919. [Year-book of the Department of 

 Agriculture, Industry and Commerce in the Dutch East Indies, 

 1919.]— Weltevreden, 1920, 387 pp. Price 4 florins. [Received 

 23rd February 1921.] 



The information here given regarding insect pests has already been 

 dealt with from the reports of the various experiment stations, etc. 



Cappe de Baillon (P.) . Contributions anatomiques et physiologiques a 

 I'Etude de la Reproduction chez les Locustiens et les Grilloniens. 

 1. La Ponte et lEclosion chez les Locustiens. — La Cellule, Lierre 



and Louvain, xxxi, no. 1, 1920, pp. 7-245, 8 plates, 15 figs. 



This extensive monograph describes the oviposition and hatching 

 of eggs of Orthoptera, both from an anatomical and physiological 

 point of view, and is the result of observations made on over 50 

 different species. 



PicARD (F.) & Pagliano (T.). Sur la Biologie de I'Altise de la 



Vigne [Haltica ampelophaga. Gu6r.).— C. R. hehdom. Acad. Sci., 

 Paris, clxxii, no. 7, 14th February 1921, pp. 399-401. 



Observations made on Haltica ampelophaga under laboratorj' con- 

 ditions show that the females are comparatively long-lived. The 



