157 



The author has recently observed a short cycle of 3-4 months in 

 the Bienwald, Rhine Palatinate, under conditions that do not 

 appear to admit of any error. 



The great difference in the duration is considered to be 

 due to variations in temperature. In support of this theory it 

 may be noted that the beetles were found in the superficial 

 roots almost exposed to sunshine at atmospheric warmth. In the 

 lower roots only larvae were found. Furthermore, on his return 

 from the Rhine Palatinate to a colder region the author found only 

 larvae. 



It is therefore probable that the length of the life-cycle of H. ahietis 

 is governed by the temperature ; in warm regions, like Alsace and the 

 Rhine Palatinate, a short period is possible. The difference in the 

 lengths of the hfe-cycles is not so surprising if it be remembered 

 that even in the case of the long period the larvae are full grown in the 

 autumn of the first year. It is possible that pupation requires a certain 

 degree of warmth. 



A further question is whether there is also a possibility of two 

 annual generations. If the beetle requires a long maturing period, 

 even the short developmental period can yield only one generation. 

 Dissection of the short-cycle females from the Bienwald showed that 

 the ovaries were quite immature. 



As regards the swarming and feeding periods, it is poinled out that, 

 though various writers believe oviposition to be spread over the whole 

 year, practical experience shows that there are two chief feeding 

 periods— in the spring and autumn. Undoubtedly the female (as 

 with Pissodes) can oviposit throughout the summer if fresh breeding 

 material is available. Such conditions are found in a virgin forest, 

 but in regulated forestry, spring is the chief oviposition period, owing 

 to the attraction due to winter fellings. In a regulated forest it is, 

 therefore, feasible to restrict most of the oviposition to a given period 

 in the year. 



The paper concludes with an appeal for co-operation, the chief 

 assistance needed being a supply of infested roots with the exact date 

 of felling. 



JMeyer (L.). Casit gegen Erdflohe. [The Use of Casit against Flea- 

 beetles.] — Deutsche landw. Presse, xlvii, 1920, p. 5. (Abstract in 

 Centralbl. Bakt., Parasit. u. Infektionskr., Jena, lite Abt lii 

 no. 18-23, 6th January 1921, p. 425.) 



A commercial preparation, Casit, is recommended by the author, 

 its manufacturer, as the best remedy against flea-beetles, as it is 

 non-poisonous and contains no arsenic. The constant use of arsenicals 

 is considered detrimental to the fertihty of the soil. 



Independent testimony is given in support of this claim. This 

 official opinion states that three applications of Casit destro3'ed the 

 flea-beetles on older plants, but that for practical purposes success 

 on 3'oung plants is more desirable, as they suffer most from the 

 infestation. 



KiEFFER (J. J.). Une nouvelle Vari^t^ de Cecidomyie (Dipt.).— 5/^//. 



Soc. Ent. France, Paris, no. 17, 10th November 1920, pp. 296- 



297. [Received 25th January 1921.] 



A description is given of Silvesirina silvestrii var. cecconiana, n., 



taken in large numbers on olive fruit in Italy. The type species comes 



