64 



SCALE PESTS OF COFFEE 



instars the bugs are more opaque than are the corresponding 

 instars in green bug. The colour may vary from dark 

 dull yellow to dark dirty brown. There are also from six 

 to eight waxy protruberances along the median line which 

 continue more or less to the adult stage. In some indi- 

 viduals, a dark brown oval object is found inside the body 

 showing through the top skin. What the function of this 

 is, is not clear. It has apparently no connection with the 

 viscera. As soon as the bug is tense with eggs, it becomes 

 more yellowish and shows for the first time the loop 

 faintly. It becomes now restless, leaves the place of at- 

 tachment and frequently moves about until it finds a 

 suitable shelter as a fold of leaf and a crevice in the bark. 

 Egg-laying takes place also in more exposed situations on 

 the leaves themselves. The bugs do not seem to want 

 any nourishment when the eggs are being laid as some 

 transferred to glass dishes laid eggs, apparently unaffected 

 by the change in condition. The life history is completed 

 within two or three months. The newly-hatched young 

 takes from fifty to seventy days to attain the adult stage. 

 The secretion of meal and the laying of eggs is completed 

 in about five days. It has not been possible to determine 

 accurately the length of life of the insect owing to the 

 difficulty of ascertaining the exact time of death. 



The following table gives the number that crawled 

 out from day to day from beneath four adult females : — 



Habits of the Insect. — The bug is not as partial to the 

 sides of the veins as green bug. A large number may 

 be found away from them or on top of them. There is, 

 however, a decided preference for more tender twigs, es- 

 pecially those springing from the stumps of trees or 

 branches cut off. On these, the bugs are usually found 

 crowded. There is a plentiful secretion of honey dew. 

 This is often so abundant as to cover the leaves not only 

 of the attacked tree but also of those below and the result- 

 ing sooty mould may be sufficiently serious to cause the 



