ENEMIES OF GREEN BUG 33 



a scale insect from the approach of a fly which wanted to 

 parasitise it. 



These results are to a great extent confirmed by obser- 

 vations made in Mysore. Two plants of about the same 

 age had bugs introduced on to them. Into one of these 

 an ants' nest was introduced on 3rd February, 1917. On 

 8th May, 1917, three months after, the plants were ex- 

 amined for parasitised bugs. On the plant with ants no 

 parasitised bug was found, while on the other the percent- 

 age of parasitised bugs was 14'3 per cent. A count of the 

 total number of bugs on the two plants gave results the 

 reverse of those recorded b}' van der Goot. The experi- 

 ment was started with six nymphs, each of third instar. 

 At the end of three months there were only 67 adult bugs 

 in the pot with ants, against 116 in the on6 without. 



It is too early to arrive at any definite conclusions 

 from the experiments. It may, however, be noted that 

 the only estate in which green bug seems to have ob- 

 tained a persistent hold in Mysore is one where the species 

 of ant experimented with in Java {Plageolepls longipes) is 

 found in abundance. It is also interesting to record that 

 while the percentage of parasitised bugs in the Laboratory 

 compound is as high as 20 per cent, in the estates it is 

 not more than 5 to 7 per cent. 



The Enemies of Green Bug. 



The most important insect enemies of green bug in 

 Mysore are the hymenopterous parasites. These lay their 

 eggs in the body of the insect. The larvse hatch out 

 and feed inside the body. Apparently the alimentary 

 canal is not affected, for the bug continues to live even 

 when the parasite inside the body is very large. Young 

 may also be produced by the parasitised bugs. There are 

 at least five species of parasites but their efficacy is seriously 

 diminished by a hyper-parasite and, as has already been 

 shown, by the attendance of ants which appear to prevent 

 their approach and oviposition. 



Frontispiece, Fig. 4, shows the general appearance of 

 green bugs when parasitised. Such bugs are to be dis- 

 tinguished by their brownish colour which can be readily 

 made out in the figure. Plate I, Fig. 7, shows a green bug 

 with the pupa of a hymenopterous parasite inside of it. 



I> 



