367 



months, and as a result the insectivorous birds that had not already 

 died of cold, then died of starvation. Certain insects, upon emergence, 

 therefore found themselves almost free from enemies, and many 

 occurred in most unusual abundance throughout the winter. Ants, 

 particularly of the genus Atta, were a veritable plague ; cutworms 

 were responsible for very serious damage to agriculture and horticulture ; 

 Diabrotica speciosa was so abundant that in some locaUties garden 

 produce was almost entirely destroyed, while D. vittata almost 

 completely devoured the winter sowings of Cucurbits ; Lepidoptera 

 were so numerous that heavy infestation by the larvae is expected 

 during the following summer season ; Noctuids, Tabanids, Haltica spp., 

 Chrysomelids, Curculionids, Aphids, Pidex, RJiyncJiojprion sp. and 

 grasshoppers were all unusually abundant. Those insects that are 

 largely controlled by insect enemies were no more numerous than in 

 normal years. 



I Gas velenosi nella Distruzione degli Insetti dannosi alle Piante. 



[Poisonous Gases for the Destruction of Insects injurious to Plants.] 

 La Campagna, Como, xix, no. 319, 15th April 1920, p. 2. 



A new company, Societa Italiana Fumigazioni Gas Tossici, has 

 been formed in Rome with the object of destroying noxious insects by 

 the fumigation of buildings, ships, goods and plants Avith poisonous 

 gases. 



Metalnikow (S.). Immunite naturelle et acquise des Chenilles de 



Galleria mellonellct. — C. R. Soc. Biol., Paris, Ixxxiii, no. 18, 

 29th May 1920, pp. 817-820. 



It has been shown in a previous paper that the larvae of G. mellonella 

 possess a remarkable immunity to those organisms that are most 

 pathogenic to man, while thay are very susceptible to saprophytic or 

 slightly pathogenic organisms [R.A.E., A, viii, 163]. In the present 

 paper the reasons for this apparently paradoxical statement are 

 discussed. It is considered that in all cases of acquired immunity 

 that have been studied, the essential factor is the alteration in the 

 activity and the susceptibility of the phagocytes. It may be said 

 that the reactions of the cell change in consequence of adaptation to 

 new conditions, and negative reactions are replaced by positive 

 reactions. In these changes in the reactions of the cell lies the 

 principal cause of acquired immunity. 



Reports on the State of the Crops in each Province of Spain on the 

 20th May 1920.— Bo/. Agric. Tec. Econ., Madrid, xii, no. 137, 31st 

 May 1920, pp. 378-393. 



The insect pests recorded during May 1920 include Malacosoma 

 (Bombgx) neustria on almond trees in Ahcante and larvae of the gipsy 

 moth, Porthetria {Liparis) disjMr, on oaks in Avila, which are causing 

 such injury that the trees will be unproductive for some years. 

 Measures are to be taken to destroy the eggs. Fruit trees, particularly 

 plums, are being largely destroyed by the attacks of Hyponotneuta 

 padellvs ; instructions have been given for arsenical treatment. In 

 Cordoba, the oaks have been infested with larvae of P. dispar and of 



