14 



MODE OF OCCUPATION OF NEW FIELDS IN A DISTRICT WELL OC- 

 CUPIED BY LEAF-HOPPERS, 



8. When a field of cane is first occupied by leaf-hoppers they 

 sometimes appear to spread over this m a very uniform manner, 

 provided always that the conditions of growth of the cane, shel- 

 ter, &c., are uniform. This can sometimes be very well seen in 

 fields of very young cane. One that was examined by me con- 

 sisted of cane about one month above ground, and on the aver- 

 age eacli plant was the home of two mature leaf-hoppers. Obvi- 

 ously these had migrated thither from adjoining fields, as they 

 could not have reached maturity on such young plants. 



Two fields of cane adjoining one another, one of Yellow Cale- 

 donia, the other of Rose Bamboo variety, each about five months 

 old held a stock of 20-50 adult hoppers to each crown, uniform- 

 ly distributed in either field. These also had come by migration., 

 for, at the time, there were very few young in these fields, and 

 the egg chambers nearly all contained unhatched eggs. This uni- 

 form distribution of hoppers over new fields, of course, only ap- 

 plies to such districts as have already in some parts, at least, a 

 superabundant supply of the pest. Their first appearance in a 

 district has (so far as such early and exact evidence as I have on 

 tlic subject goes) generally been limited to a quite small area of 

 one plantation. 



ON STRIPPING CANE IN LEAF-HOPPER ATTACK, 



f 



9. As I have incidentally mentioned, leaf-hoppers like the 

 more sheltered spots and hence it can sometimes be seen that they 

 are in less numbers in well stripped fields than in those that are 

 not stripped. This probably means nothing more than that the 

 total number of the insects present are more unevenly distributed 

 than would be the case were all fields stripped. Probably not many 

 of the pest are destroyed by stripping, since most of the eggs laid 

 in such leaves as are stripped have already hatched, and those 



