16 PESTS OF COFFEE 



been introduced by their enormous variability. In Mysore 

 the number of young brought forth has varied from 50 to 

 580. The following charts (see Text-figs. 3 and 4) show 

 for each individual reared in the insectary the number 

 of young produced from day to day and the total for the 

 whole period of life. 



This great variation in the number of young pro- 

 duced depends on various different factors of which the 

 size of the bug, the age of the leaf on which the bugs 

 fix and the place of fixation are only a few. The bugs 

 on the more tender and young leaves and on the 

 developing shoots are healthier and grow more rapidly. 

 Those bugs along the veins and on the under side of the leaf 

 are in more favourable situations than those on the upper 

 • surface of the leaves. There are, in all probability, other 

 factors, such as humidit}^, temperature and the vigour of 

 the plant, whose influence it has not been possible to de- 

 termine. 



The bugs which have begun to reproduce can be re- 

 cognised by the more whitish appearance at the pos- 

 terior end, due to the white egg shells which accumulate 

 beneath. The posterior margin is also slightly tilted up 

 to allow the young to crawl out. On some plants, 

 especially those blackened by sooty mould, this is quite 

 conspicuous. The upper surface of the body may be 

 thrown into minute folds, due no doubt to the posterior 

 end of the body being forced up by the accumulation of 

 the young underneath. 



The insect is ovoviviparous; in other words, the eggs 

 develop inside the body and hatch at the time of or im- 

 mediately after extrusion. The under surface of the abdo- 

 men is slightly arched to allow space for the young which 

 remain beneath the mother for some time. When the 

 scale is lifted oil[ from the leaf one or two eggs may 

 occasionally be detected amidst the young entangled in the 

 egg shells. 



The process of fixation of the njanphs appears to be a 

 difficult one and takes some considerable time. At the 

 commencement of the operation the young nymph is found 

 at an angle to the surface of the leaf, the hind end touch- 

 ing the leaf, The tip of the proboscis alone is apparently 

 inserted during this period which is very short. It is 

 followed by a slant in a reverse direction the anterior end 

 being nearer the leaf, When balanced this way the bug 



