ON THE LIFE HISTORY OP UGIMYA. 



15 



in its development. In June, the flies decrease in number, and con- 

 sequently deposit a fewer total number of eggs. This is easily seen 

 from the small number of flies Avhich frequent mulberry bushes, and 

 from the scarcity of eggs attached on the leaves sprouted after the 

 month of May. 



Though the eggs are firmly attached on the under side of the 

 leaves, they can be easily removed by wetting them with a few drops 

 of water, for tlie water softens the sticky substance wäth which the eggs 

 are attached. The eggs do not difi^er from those contained in the 

 vagina in their form and size. ]5oth the surfaces of the egg are marked 

 out into hexagonal areas, which on the flat surface are however almost 

 always rather indistinct. Its convex surflice, colored dark brown 

 and of a chitinous nature, has a lustre, while the opposite or flat sur- 

 face, colored greyish brown, is membranous and destitute of a lustre, 

 so that the contained maggot can be distinguished only when looked 

 at from this flat surface ( PL II, fig. 7 ). 



As a general thing, eggs laid on the leaves sprouted during the 

 month of May remain alive during the month of June, but later they 

 are destroyed by the severe summer rays of the sun. Thus even where 

 leaves from the same bushes are given to the summer and autumnal 

 breeds of the silkworm, which appear respectively in the months of 

 July and August, they are much less affected by the " Uji " than the 

 spring breed. And, for the same reason, the winter breed is entirely 

 free from this parasite. 



As stated in the previous section, the depo.'^ition of the eggs of the 

 fly takes place most abundantly in the last part of May viz : — at the 

 time when the silkworm is in its third or fourth moult. Accordingly, 

 at this period, the silkworm takes the eggs of the fly most frequently 

 into its body, and it does this by taking them along with the mulberry 

 leaves which serve as food. At first thought it might seem as if the 



