20 PESTS OF COFFEE 



obscure. I have myself observed the shedding of the skin 

 in the genus Lecanium. The exuvium is very thin and 

 delicate becoming twisted up into a minute formless shred 

 as it is pushed off the body. The old skin may sometimes 

 be seen still adhering to the posterior extremity of a re- 

 cently transformed female fjecanium. It is difficult to 

 understand how such genera as Ceroplastes or Vinsonia 

 in which the waxy test is closely adherent to the body 

 of the insect through life can get rid of their exuvia. It 

 is possible that the cast skins may become incorporated 

 into the waxy test. The fact that in Ceroplastes the pad 

 of opaque wax that covers the dorsum of the larva may 

 always be recognised as a central spot on the test of the 

 adult and the pointed lateral processes of the larval test 

 can be distinguished at intervals in the sub-marginal area 

 of the fully formed test, lends colour to this theory of in- 

 corporation." 



The process of moulting in green bug described above 

 is the same as that found in the mealy bug and brown 

 bug, and there can be no longer any doubt as to the theory 

 of incorporation advanced by Green. How the marginal 

 separation of the top and ventral skins is effected is not 

 clear. Green bugs are occasionally found with the whole 

 body tense, translucent and markedly convex. This may 

 possibly help in the separation. It has to be noted, how- 

 ever, that this feature does not appear dufing or imme- 

 diately before a moult. The bugs when casting skins 

 cannot be distinguished from others save for the shred of 

 skin gradually rising between the anal lobes. The moult- 

 ing is followed by a period of restlessness, the bugs seeking 

 new places of attachment. With the third moult the 

 bug reaches the adult stage. After the last moult, the 

 bug becomes gradually convex on account of the develop- 

 ment of the eggs within. 



Description of Stages or Instars. 



1st Instar. 



Light lemon-yellow. Broadly oval. The hind margin interrupted 

 in the middle, the ends curved inwards and disappearing beneath the 

 apices of the anal plates which are completely within the oval outline. 

 The anal plates are terminated behind by two long filaments. The 

 eyes are near the margin. The abdominal segments are indicated by 

 minute folds. The thoracic divisions are also traceable but with diffi- 



