160 



H. A. TEMP ANY AND D EMMEREZ DE CHARMOY. 



measures has been to circumscribe to a large extent the infested area, and to mitigate 

 the damage caused thereby. Had these measures not been applied, it seems reason- 

 ably certain that the cane-growing industry, at any rate in the lower regions of the 

 island, would have sustained much more serious damage than has actually been 

 experienced. 



At the time of the first outbreak, no properly constituted authority existed for 

 dealing with administrative measures directed to the control of plant pests and 

 diseases, and consequently two committees were appointed, charged with the super- 

 vision of the work of control, one being a consultative and the other an executive 

 body. At the same time the present Entomologist of the Department of Agriculture, 

 who then held the office of Curator of the Mauritius Institute and Museum, was 

 appointed temporarily for executive work in connection with the operations, the 

 work being attached, for administrative purposes, to the Department of Forests. 



On the formation of the Department of Agriculture in 1913, the control of these 

 and other operations against plant pests and diseases was transferred definitely 

 to the control of this Department and has remained thereunder ever since. 



The Habits of the Beetle and the Damage done by it. 



The character of this Melolonthid beetle and the nature of the damage occasioned 

 by it are now too well known to need any detailed description, and for a complete 

 account of the various stages in its life-history reference may be made to the report 

 on Phytalus smitlii by one of us (D. d'Emmerez de Charmoy), previously referred to. 



Only one generation is produced per annum. Though the period of the greatest 

 emergence does not last more than 3 to 4 months, from November to January or 

 February, these insects can be found in the adult stage all the year round in varying 

 numbers, according to the season, the development being to some extent dependent 

 upon climatic conditions. Soil temperature and soil moisture are factors influencing 

 the duration of the pupal and larval stages, as well as the incubation of the eggs. 



The following table brings out the difierence existing between insects reared at 

 Phoenix, at an altitude of 1,311 ft., and those reared at Pamplemousses, where the 

 altitude is 208 ft., the temperature being in the latter district much higher than in 

 the former. 







No. of days 



Kemarks 





Minimum 



Maximum 





Egg stage 



Larva : active 



inactive — prepupal 

 Pupa 



r prior to emergence from soil . . 

 first copulation after emergence 

 Imago \ copulation 



laying perod 

 . after tbe laying period 





7 

 210 

 30 

 18 

 10 

 10 

 60 

 30 

 30 



23 



240 

 45 

 25 

 15 

 15 

 75 



120 

 90 



Maximum at 

 Phoenix in 

 September. 

 Minimum at 

 Pamplemous- 

 ses in Decem- 

 ber 







405 



648 





