75 



11 to 44 days after emergence, and lasts for an average period of 

 65 days, the female living about 11 days after oviposition has ceased. 

 During this period an average of 212 eggs are laid in one or two straight 

 rows along the midrib on the upper leaf surface. The incubation 

 period in the laboratory lasted 6 to 8 days. The nymphal stage lasts 

 17 to 23 days, during which time five moults occur. A list is given of 

 wild grasses on which L. acuta can subsist and breed when rice is not 

 growing. 



Natural enemies of the bug are the predacious tiger beetle, Cicindela 

 sexpunctata, which is an active check in India and has been recorded 

 from the Philippines, and a Proctotrupid egg-parasite. These should 

 be encouraged, and other beneficial insects from rice-producing 

 countries should be imported. 



In view of the seasonal appearance of L. acuta, a small area should 

 be planted with rice that wiU reach the milk stage earlier than the 

 adjoining rice fields ; this will attract any rice bugs in the vicinity. 

 Planting should be regulated so that the rainy-season rice will attain 

 the milk stage, the only one attacked, at about the same time in a 

 given locality. Certain varieties of rice, especially the bearded ones, 

 appear to be less susceptible to attack than others, and the production 

 of immune or less susceptible strains by breeding and selection is dis- 

 cussed. Several small areas planted with early rice, as described 

 above, might be used as traps, and the plants burnt when the adults 

 have collected on them and oviposited for some time. The adults can 

 also be trapped by suitable baits, such as decaying meat. Elongated 

 bags dragged across the field, as practised in India, also catch many of 

 them. Clean culture of the fields, both during and after the rice 

 season, is essential. During the season, wild grasses should be weeded 

 out both from the fields and dykes. • After the harvest the ground 

 should be ploughed and planted with another crop and not allowed 

 to become overgrown with weeds, as is frequently the case in the 

 Philippines. Where cheap labour is available, hand collection of the 

 eggs is a useful accessory measure. 



Contact insecticides, such as kerosene emulsion, applied with a 

 knapsack sprayer, might prove a successful remedy. This treatment 

 need only be applied during the one month occupied by the milk stage. 

 The nymphs usually congregate on the panicles during the cooler 

 parts of the day ; spraying should therefore be directed to that part 

 of the plant in the early morning or late afternoon. The spray should 

 be applied rather frequently during the month in order to catch 

 any bugs that have fallen to the ground or escaped the previous 

 treatment. 



Meyrick (E.). Exotic Microlepidoptera. — ii, pt. 15, November 1921, 

 pp. 449-480. [Pubhshed by the author, Marlborough, Wilts. 

 Price 3s. per part.] 



Of the new species described the following were bred from plants 

 of economic importance : — Mesopotamia : Pyroderces philocarpa, from 

 fallen dates ; Tahiti : Decadarchis psammanla, on tips of coconut 

 leaves ; Ceylon : D. p achy gramma, from coconut ; British Guiana : 

 Blastobasis ochrobathra, from blossoms of coconut palm ; and Fiji : 

 Agonoxena argaula, from leaves of coconut. 



(5441) F 2 



