X.\TUR.\L ENEMIES OF MANGO LE.VF-HOPPERS. 



467 



It is not definitel}- known on what these cateipilhus feed. To lincl this out, 

 a number of hoppers with the parasites in different stages were minutely observed 

 in captivity. The larger caterpillars were found to irritate (scrape?) the sides 

 of the abdomen with the mouth-parts, and the young caterpillars treated in the 

 same way the soft portions between the abdomen and the thorax dorsally. Very 

 small quantities of some whitish wax-like matter was noticed all about the cater- 

 pillars, but no damage to the abdomen of the hoppers was evident. I am not sure 

 if they fed on this white waxy matter. The hoppers seemed in no way inconvenienced 

 by the presence of these parasites on them, and they were alive and (juite active for 

 a long time after the parasites had left them for pupation. 



Pupation takes place underneath the leaves of the mango or on the stems, in 

 a bright white tough silken cocoon (PI. xvi, fig. 3). If the parasites are on /. niveo- 

 sparsus, pupation takes place on the main trunk and branches where the hoppers 

 rest ; if they are on the other two species, pupation takes place underneath the leaves. 

 In 1919 the white cocoons of these parasites were found in such large numbers 

 underneath the leaves and on the trunks of the trees in a garden in Bangalore, that 

 they were at first mistaken for a bad attack of the common scale-insect, Pidvinaria 

 psidii ; but the absence of " sooty mould " and the shining appearance on the leaves 

 were very marked. The caterpillars do not act as a control on the hoppers to the 

 slightest extent. 



4. The Dryinid Wasp. 



During the mango blossoming season m.any of the hopper nymphs were found 

 moving on the flower-stalks and leaves with small, dark, round objects attached 

 to the pleural side of the posterior end of the third segment of the thorax, which were 

 found to be the grubs of a Dryinid wasp. There is a dark sac-like covering enclosing 

 the grub, which is cast off along with the moulted skin of the hopper nymphs. 



The full-grown grub is of a rich cream colour, very thick at the posterior end 

 and tapering to a point anteriorly (PI. xv, fig. 7). Pupation takes place in a thin 

 silken cocoon. We have not yet been able to rear the adults from the grubs in 

 captivity, so that the species has not been identified. In no case were the nymphs 

 found to survive the attack of the parasite. All the three species of hoppers were 

 attacked. 



:^ ^ ^ i\: :!(: :^ :^ ■:^. 



The following table shows the percentage of parasitism of tlie hoppers by the 

 different parasites. 



In conclusion I have to state that the above observations were made by me in 

 the mango gardens in Bangalore ; the study of the life-history and bionomics is 

 being continued. I am greatly indebted to Dr. Coleman, the Director of Agriculture 

 in Mysore, for the read\' help and great encouragement shown to me. 



