419 



either that or a normal ripening of the food- plant in autumn. Partheno- 

 genetic reproduction may in many species be indefinitely continued 

 in a warm climate or in hot-house conditions. Whetlier temperature 

 is the direct control is doubtful, for many species produce both alate and 

 apterous forms throughout the summer ; and it is quite possible that 

 continuous vegetable growth in a warm climate is the direct encourage- 

 ment to parthenogenetic viviparous reproduction. Even in tropical 

 v'lunates with a wet and dry season gamogenetic eggs are produced to 

 tide over the period of famine ; and in the north some non-migrating 

 species produce sexuales in August, July or even June on exhausted 

 vegetation. Certain species, such as E. lanigeruni and Prociphilns 

 fessellatiis, even when they occur in the north, attempt to provide for 

 a continuation of the apterous viviparous parthogenetic part of their 

 cycle by producing annually nymphs to hibernate about the base of the 

 secondary host at the same tune that the migrants are producing the 

 sex forms on the primary host. 



In the case of Coccids, the specialisation of their structural characters 

 and the modified metamorphosis of both sexes is discussed, and typical 

 life-cycles of Coccidae in general, and of Xylococcns betulae and 

 Aspidiotus pern'ciosiis in paiticular, are sketched. 



.Seamans (H. L.). The External Anatomy of Anthomijia radicum, L. 

 (Diptera Anthomyidae). — Ami. Entom. Soc. America, Columbus, 

 Ohio, xiii, no. 2, June 1920, pp. 201-223, 6 plates. 



The contents of this paper are indicated by its title, 



HiCKERNELL (L. M.). The Digestive System of the Periodical Cicada, 



Tibicen septemdecim, L. — Ann. Entom. Soc. America, Columbus, 

 Ohio, xiii, no. 2, June 1920, pp. 223-242, 6 plates. 



In discussing the structure of the digestive system of Tibicen septem- 

 decim, it is remarked that nothing in the course of the present 

 study has thrown any light upon the reasons for the peculiar life- 

 history of this species. 



JouLiAN (C). A Coleopteron injurious to grafted Vines in Algeria. — 



La Petite Revue Agric. et Hortic, Aniibes, xxvi, 1920, p. 10. 

 (Abstract in U Agric. Colon., Florence, xiv, no. 6, June 1920, 

 p. 272.) 



In Algeria grafted vines have a dangerous enemy in the beetle, 

 Pentodon punctatus, the underground grub of which attacks the scar 

 at the point where the grafting meets the American stock. The 

 nurseries are usually placed in ground riqh in humus as a result of 

 continued applications of stable manure, and an essential preliminary 

 to establishing a nursery is the collection of all the grubs present, any 

 adults found being also destroyed. 



EscHERicH (K.). Forstentomologische Streifzuge im Urwald von 

 Bialowies. [Forest Entomological Excursions in the Virgin Forest 

 of Bialowies.] — Bialoivies in deutscher Verwaltung, Berlin, no. 2, 

 1917, pp. 97-115, 19 figs. [Received 28th July 1920.] 



The observations recorded here were made in August 1916, during 

 a month's visit to the forest of Bialowies in Lithuania. Some portions 

 (708) a2 



