1 148 SERICULTURE 



The percentage of dry matter was also 8 to 15% higher than that of 

 the control group in the mature worms, and 5 to 7 % in the dry cocoons 

 and the silk cocoons. 



The weight of calcium contained in the groups under experiment exceed- 

 ed that of the control group in all cases, both in the mature worms and 

 in the silk cocoons ; in the larvae the excess was 25.14 % in the calcium 

 acetate group, while it was lower than this, namely 3.07 and 11.93 % re- 

 spectively, in the calcium bicarbonate and chloride groups. 



The investigations will be continued in order to ascertain which lime 

 salt is most favourable to the growth of the worms and in what degree of 

 concentration. 



It is finally pointed out that according to an analysis bj- Xagaka 

 MuNEYOSHi the ash of the ripe Japanese mulberr)^ leaf contains : 



Phosphoric acid 12.02 °b Sulphuric acid 4.65 % 



Potash 31.47 Chlorine 0.06 



Soda 3.16 Silicic acid 1.43 



I<ime 3315 O.Kide of iron 1.59 



Magnesia 12.48 



Ivime is therefore present in a proportion almost three times that of 

 magnesia ; this excludes the possibility of its beneficent action on the lar- 

 vae being due to an antagonism to the action of magnesia, similar to that 

 observed in plants. 



891 - Study of Sericulture in Madagascar. — in Bullet in economiquc de la colonie de Mada- 

 i^ascar et dcpcndances. Year 15, No. i, pp. 1-17, Tananarivo, ist Half Year 1915. 



Before the French occupation, the silk used bj' the natives was obtained 

 exclusively from Borocera madagascariensis, occurring very widely in 

 the central and western parts of the island and on a considerable number of 

 plants. It sometimes becomes a positive pest in the mimosa plantations. 

 It is still regularly reared on the " tapia " {Upaca clusiacea) which exist 

 in more or less dense forests on the lateritic hills. The " tsitoavina " 

 {Dodonea madagascariensis) and the " ambrevade " {Cajanus indicus) 

 are also reared. In the regions of Majunga and Maintirano, Borocera lives 

 wild in the Rhizophora forests of the coast and the natives gather cocoons 

 at certain periods of the year. 



There are other wild native larvae belonging to certain silk-bearing 

 species of Bomhyx ; namely B. Radama and B. Diego. They are found in 

 almost all the forests of the eastern slope and the North. The cater- 

 pillars have the peculiar feature that they enclose their cocoon in a large 

 envelope which they weave in common and which is sometimes I metre in 

 length. Since the French occupation, especialh' since 1900, the silk indus- 

 try" in the island has been based on the rearing of Bomhyx mori. 



After dealing with the cultivation of the mulberry tree i) and the tech- 

 nical conditions of silkworm breeding 2), some information is given on the 



(i) vSee B. March 1913, No. 267. 



(2) See B. June 1914, No. 555. (Ed.) 



