614 



Sixz ( — ). Ueber das Auftreten der Fichtenblattwespe {Ncmatiis 



abietiniim, Hrtg.) im Naunhofer Wald. (riie Occurrence of the 

 Spruce Sawlly, N. abicliniDii, in the Naunhof Forest.] — Tharandt. 

 forst. Jahrb., Ixxi, 1920, pp. 194-214. (Abstract in Zcitschr. 

 angew. Ent., Berlin, viii, no. 1, September 1921, p. 219.) 



Spruce in the Naunhof forest in Saxony was injured in 1919 for 

 tlic twenty-sixth year in succession by Lygaconematus pini, Retz. 

 {Nematus abietiniim, Htg.). Between 1894 and 1903 a steady increase 

 was noticed ; from 1904 to 1917 alternating increase and decrease ; 

 and since 1917 again an increase. This sawfly spreads from west 

 to east in the direction of the prevalent winds. Most of the spruce 

 trees are likely to die. Piceapungens, P. sitchensis and P. engelmanni 

 are also attacked, while P. alba seems to be almost immune. The 

 natural enemies of L. pini include tits, wood-pigeons, starlings, a 

 Hymenopterous parasite, which infested 2 per cent, of the larvae 

 in 1919-20, and a fungus, Botrytis tenella, which infested 8 per 

 cent. In stands it is difhcult to apply any remedy, but in plantations 

 of young trees spraying with Paris green has given good results. 



Keller (C). Zuckererzeugung in den Larchenwaldungen des Wallis. 



[Sugar Production in the Larch Forests of the Canton of Valais.] 

 — Natur unci Technik, 1919-20, no. 8. (Abstract in Zeitschr. 

 angew. Ent., Berlin, viii, no. 1, September 1921, pp. 221-222.) 



During an outbreak of Lacliniis laricis, Koch, in larch forests in 

 Switzerland at an altitude of about 5,600 feet, the honey-dew produced 

 covered the needles and twigs with a sugary coating. The dried 

 substance consisted of 22 per cent, grape sugar and up to 30 per cent, 

 beet sugar. The outbreak is ascribed to a previous prolonged dry 

 period. Similar occurrences are known from France (Briangon), but 

 the insect concerned is apparently vmknown. 



J EG EN (G). Zur Biologie und Entwicklungsgeschichte einiger Erio- 

 phyiden nebst systematischen Bemerkungen. [A Contribution to 

 the Biology and Developmental History of some Eriophyids, 

 with Systematic Remarks.] — Chiir, 1917. (Abstract in Zeitschr. 

 angew. Ent., Berlin, viii, no. 1, September 1921, pp. 222-223.) 



Though the injury usually done by gall-mites of the genus Eriophyes 

 is unimportant, the occurrence of very large numbers of them may 

 prove serious. 



The development and biology of these mites is discussed, with 

 special reference to Eriophyes tiliae and E. avellanae, of which 

 E. vermiformis is treated as a synonym. 



Urich (F. W.). The Mango Midge.— Z?////. Dept. Agric. Trinidad 

 & Tobago, Port'Of-Spain, xix, no. 3, 1921, p. 110. 



Mangos suffer from the attacks of a small midge in seasons when it 

 is not sufficiently kept in check by its natural enemies. Oviposition 

 occurs in the youngest flower and leaf buds, and the young larvae 

 bore into the tissues and form small swellings, inside which they feed 

 on the sap until the young leaves and flowers die. Small decayed 

 spots also appear on the flower-stalks, through which injurious fungi 

 can invade the plant. After 10 to 14 days the larvae emerge from 

 the shoots and fall to the ground, where they construct cocoons of silk 



