211 



observed to search for those infested with parasites {Aphidius sp ?) 

 and, having gnawed a ring round the body of the insect, to extract the 

 larva of the parasite and carry it away. A parasite of PsylJa pyricola, 

 Forst., was observed, but not yet identified, no parasites of this insect 

 having been previously known. Only infested nymphs were found, 

 the body being fixed to the surface of the leaf with web produced by 

 the parasite before pupating ; kerosene lime emulsion, while destroying 

 the larvae and nymphs of Psylla, proved harmless to the parasite. The 

 life-histories of the moths, Orgyia prisca, Stgr., and Amicta armena, 

 Heyl., were also studied. 



The report for the last year is incomplete, as the author has been 

 called up for military service. In dealing with the campaign against 

 locusts, it is stated that the disappearance or decline of D. maroccanus 

 in some parts of the Starvation Desert may be due to the cutting of 

 irrigation channels, which has been followed by a large invasion of 

 birds. Observations on Locusta migrator ia and L. danica show that 

 the eggs of L. danica are able, under favourable conditions, to hatch in 

 about 16 days, while those of L. migratoria hibernate, the development 

 of the embryo stopping at a certain stage. Thus L. danica frequently 

 gives rise to a second generation, and once even a third was observed 

 late in autumn. The second generation, however, in its adult stage 

 usually loses some of the typical characters of danica (such as the bow- 

 shaped outline of the pronotum and the red tibia of the hind leg), but 

 the size of the males remains small. At the same time, examples of 

 L. migratoria were found together with these in the open in 1913 having 

 red tibiae instead of yellow ones. This question is however further 

 complicated by the fact that eggs obtained by crossing a male of 

 danica wdth a female of migratoria partly gave rise to a second genera- 

 tion and partly hibernated, while from those obtained by crossing the 

 same male Avith a danica-\\]s.Q female of migratoria, no second generation 

 was obtained. It is thought to be impossible to define limits for these 

 species and L. danica is regarded as being a variety in the act of 

 separating from the parent species. Experiments confirming the 

 occurrence of parthenogenesis in Locusta migratoria^ D. maroccanus and 

 C. italicus are described. 



Observations were also made on the biology of the following beetles, 

 Polyphylla tridentata, Rtt., P. adspersa, Motsch. and MeMontha afflicta. 

 Pall. The first-named species prefers shaded soil ; the adults take prac- 

 tically no food, each female lays about 30 eggs, usually two or three 

 days after the exit from the soil ; the development of the egg lasts 

 28-31 days, the larvae moult twice and live three or four years before 

 pupating, the majority of them hibernating twice in their third stage. 

 P. adspersa usually lives in the soil of orchards and has a similar 

 development. No descendants were obtained from crossing males of 

 adspersa with females of tridentata, although a few eggs were laid, as 

 in the case of unfecundated females, but normal oviposition was 

 obtained by crossing males of tridentata with females of adspersa, 

 though the larvae were weak and did not mature. 



The income of the Station for 1912 amounted to nearly £1,000, and 

 for 1913 and 1914 to about £800, the money being provided partly by 

 the Local Authority and partly by the Department of Agriculture. 

 In addition, some £500 was spent in 1914 on the actual campaigns 

 against insect pests. 



