Tl8 ON THE SCALE INSECT OF MULBERRY TREES. 



margins of the same is beset with four pointed strong processes 

 arranged at regular intervals. When a nearly circular depressed 

 cocoon (scale) attains about i mm. in diameter, the pupa be- 

 neath it undergoes the last or third moult. The moulted skin 

 which is of a dull brownish red color, becomes also part of the 

 scale, thus the brownish red mark on a fully formed scale is 

 nothing else than the moulted-skin of a pupa (Fig. 9. b. PL. I.). 



At the moment of moulting, the pupa-skin is split up lon- 

 gitudinally on its ventral surface, and a female insect may 

 come forth. Remaining in the same position, that is, exactly 

 beneath the moult-skin, it attaches itself firmly to the bark by 

 penetrating it with its long filamentous rostral setae. The newly 

 hatched female scale insects secrete also fine threads from the 

 pores, which open on the posterior region of their bodies, and 

 these secretions accumulate at the periphery of the already 

 formed scale, thus increasing its dimensions. In this way the 

 scales attain their normal size. 



The scales (Fig, 21. PL. II.) are formed either in groups or 

 are scattered sparsely over the bark of twigs or branches, and 

 most of them, lying beneath the epidermis of the bark, present 

 a dull greyish yellow aspect, which makes it very difficult for 

 us to observe (especially when they lie very sparsely), owing 

 to their color being similar to that of the bark. 



As I have mentioned before, our scale insect breeds only 

 twice a year; instead of three times, like the species Diaspis 

 pcntagonia Targ. observed by Mr. Y. Contagne. 1 



IV ) Determination of the Species of the Scale Insect, 



The want of sufficient literature on the scale insect makes 

 it very difficult to determine its exact species. But still we 

 may say the scale insect of the mulberry trees unquestionably 

 belongs to the genus Diaspis whose characteristics Mr. Albert 

 C. F. Morgan 2 has described in his work " Observations on 

 Coccidae." Its specific characters agree to a certain extent 

 with those of the Diaspis pcntagonia, Targ., which Messrs 

 Targioni-Tozetti and Francescbini, 3 and also Mr. G. Coutagne 1 

 have very accurately described ; but still some differences may 

 exist between Diaspib pcntagonia, Targ, and our Japanese scale 



