260 



to indicate that this method may be useful in depositing a film of 

 arsenic on tall trees. The degree of toxicity attained did not seem 

 sufficient to kill the older larvae in this instance. The sudden advent 

 of frosty weather ended the infestation. 



Zacher ( — ) & WiLKE ( — ). Beobachtungen uber Drahtwiirmer und 



Lupinenfliege. [Observations on Wireworms and the Lupin 

 Fly.] — Mitt. Biol. Reichsanst. Land- ii. Forstimrtsch., Berlin, 

 no. 21, December 1921, pp. 104-110, 4 figs. [Received 13th 

 March 1922.] 



Considerable damage was done in 1920 to potatoes at Kopemitz 

 owing to infestation by Agriotes ohscurns, L., and Selatosomus aeneus, 

 L. Experiments with poison-baits for these wireworms showed little 

 prospect of practical success ; heavily poisoned baits were neglected, 

 while those lightly poisoned did not seem to kill the larvae. Breaking 

 up the soil in late summer to a depth of 6 in. is a measure commonly 

 advised, but in August the older larvae were already at a depth of 

 8-12 in., probably owing to the light soil. 



In the same locality young plants of lupin grown for manure were 

 attacked in August by Phorbia {Chortophila) trichodactyla, Rond. 

 This was the long sought for autumn generation of this fly, observations 

 having hitherto been confined to the spring generation. 



BoRNER ( — ). Ueber die Umwandlung von Wurzelreblausen zu Blat- 

 treblausen. [The Transformation of the Root Vine-louse into the. 

 Leaf Vine-louse.] — Mitt. Biol. Reichsanst. Land- u. Forstwirtsch., 

 Berlin, no. 21, December 1921, pp. 163-167, 3 figs. [Received 

 13th March 1922.] 



In 1908 Foa and Grassi observed a spontaneous transformation of 

 root forms of the vine-louse [Phylloxera] into aerial forms. The author 

 tried to effect this change by reproducing the conditions attending 

 the Italian investigations, and was successful after a first unsatis- 

 factory attempt. Though an exact determination could not be made, 

 the Aphids that transformed appeared to be the pervastatrix form. 

 The method used was as follows : A well-pruned pot vine was placed 

 under a glass cover in a greenhouse, and the densely infested roots 

 from another pot vine were laid on the soil in the pot. Care was 

 taken to allow the foliage to develop in the manner peculiar to shaded 

 plants. Most of the Aphids on the exposed roots sought refuge in 

 the soil, but some remained on the exposed roots and oviposited there. 

 Some young Aphids, however, migrated to the foliage and produced 

 galls on it. The eggs of these gave rise to young with the biological 

 and structural characters of the leaf form in all important respects. 

 This method provides an easy means for investigating the races of 

 Phylloxera that occur in the infested regions of Germany. 



BoRNER ( — ) & Thiem ( — ). Neuere Mittel zur Reblausbekampfung. 



[New Methods for Combating the Vine-louse.] — Mitt. Biol. 

 Reichsanst. Land- u. Forstwirtsch., Berlin, no. 21, pp. 167-182. 

 [Received 13th March 1922.] 



Investigations of the method for destro^ang Phylloxera by means 

 of Ergethan (a tetrachlorethane cake insecticide that has been used 



