483 



Cleghorn (M. L.). a Note on the Vitality and Longevity of Silkworm 

 Moths during the Cold and Rainy Seasons in Bengal. — Jl. ^- Proc. 

 Asiatic Soc. Bengal, Calcutta, xv, no. 2, June 1919, pp. 101-105, 

 2 plates. 



Observations made in Bengal to ascertain the time of maximum 

 vitality and longevity of silkworms show that the moths stand changes 

 of temperature better than rises of humidity. For this reason vitality 

 was lowest in the rainy season in August and September, almost 

 stationary in April, May and June, and highest in December. 



The moths used for these experiments, which are being continued, 

 are now in their 5Gth generation. 



A table is given showing the exact length of life of all individuals 

 and the duration of the respective larval and pupal stages. In 

 December the length of life of the moths was 19 days and over, whereas 

 in August the average was only 3 days. 



Notes on Insects in Seychelles. — MS. received from the Colonial 

 Office on 6th September 1919. 



In consequence of the continued depredations of Oryctes rhinoceros 

 (rhinoceros beetle) a bill has been prepared giving power to the 

 Agricultural Department to eradicate the beetle at the expense of 

 the owner from plantations that are not properly looked after, and 

 also to deal with accumulations of rubbish in which the beetle breeds. 

 Tcclinomyrmex albipcs, the small black ant that has been a very 

 troublesome household pest in the low country at Mahe for the past 

 ten years, has gradually disappeared, perhaps owing to the gradual 

 reduction in the numbers of scale-insects, Coccus [Lecanium) vindis, 

 Eucahjmnatus (L.) (esscllatus, Ceroplastes rubens, etc., which have 

 been largely controlled by the fungus, Cephalosporium lecanii, intro- 

 duced from Ceylon in 1911. This fungus, has spread all over the 

 colony in a short time ; its spread is dependent upon rainfall, the 

 spores being more actively disseminated during the rainy season. 

 It is proposed to introduce from South India another fungus, Empusa 

 lecanii, which destroys the green scales even during cold weather. 

 Spraying should be continued against the scae-insects that still 

 remain in sufficient numbers to cause a fresh outbreak of infestation 

 if dry weather should prevail for a long time. In the Praslin group 

 of islands the fungus disease has not succeeded in controlling the 

 scale-insects, which are causing severe damage, but the new 'species 

 will be tried in these localities. 



Among the insects identified during the year are Argijroploce 

 aprobola, Meyr., a moth that oviposits on leaves of Hibiscus 

 abelmoschwi and greatly interferes with the culture of this plant 

 except in places 'where the soil is so rich that its growth is 

 vigorous enough to outgrow the attaclcs. The caterpillars may be 

 killed by spraying every fortnight with lead arsenate. The Gracilariid, 

 Acrocercops angelica, Meyr., was found in the Praslin islands attacking 

 leaves of Calophgllum inophyUum, Sideroxylon attenuatum and other 

 plants. As many as 50 eggs may be laid on one leaf, and as the 

 caterpillars eat out large holes in them the trees become rapidly 

 defohated. This moth is indigenous and is giving considerable trouble 



