Mr. Jhaveri. 
Mr. Fletcher. 
Mr. Ghosh. 
Mr. Fletcher. 
Mr. Kunhi 
Kunnan. 
Mr. Fletcher. 
~ 
24 PROCEEDINGS OF THE SECOND ENTOMOLOGICAL MEETING 
In Bombay, Incosopol was tried against mango-hoppers. Thirty- 
six mango trees were sprayed just when they were coming into flower. 
Three sprayings were given in all, a wheeled sprayer being used for the 
purpose, and the ieeencde used at a strength of one pound to ten to 
fifteen gallons of water. The sprayed trees yielded 3,000 to 4,000 
fruits and this yield was decidedly much more than that of the un- 
sprayed trees, The cost of three sprayings came to three to four annas 
per tree, including labour charges. 
Spraying is effective provided that it is started soon enough and 
carried on sufficiently. As regards the best material to use, this is pro- 
bably largely a matter of local cost. The Fish-oil-Resin Soap, obtain- 
able in Malabar, is the cheapest in Madras ; further away, the cost of 
freight will add to the price. Crude Oil Emulsion requires to be used 
fairly strong, one part in 25 to 30 of water. Mr. Ramakrishna Ayyar 
told us that he used it at a strength of 1 part in 100 of water and possibly 
that accounts for its lessened efficiency as compared with the Fish-oil- 
Resin mixture. Incosopol, used in Bombay, is a new insecticide pre- 
pared by the Indian Cotton Seed Oil Company at Navsari, near Surat. 
It requires to be tested before we can recommend it, but it is probable 
that a vegetable oil preparation will be less harmful to foliage than a 
mineral-oil mixture such as Crude Oil Emulsion. The question of local 
cost also comes in and what may be cheaper in one district may be 
more expensive in another. Sprayings require to be repeated because- 
the sprayed trees may be reinfected and because the eggs and some 
hoppers may escape the effects of one spraying. The life-cycle of 
Idiocerus is extraordinarily short, something like eight or nine days. 
The hoppers are found throughout the year. It is only at the flower- 
ing-season of the mango that they have opportunities of multiplying 
very quickly. From fe time of hatching to the adult state the bug 
takes seven to nine days. At the flowering-season, on account of the: 
abundance of tender stems and shoots, they multiply quickly and their 
number rapidly increases, and that is why such large numbers are found 
at that time. At other times of the year they breed, but only on tender 
leaves when these are available, and therefore their numbers cannot 
increase very much. 
We seem to know very little about any natural checks on the increase 
of Idiocerus. We do not know of any parasites and, if there are any, 
they do not seem very effective. 
In Mysore I have found a small moth whose caterpillar parasitizes 
Idiocerus \ exhibited]. 
It is quite a novelty and appears to be an Epipyropid. It is evidently 
a new species and probably belongs to a new genus. 
