WT 



376 TEOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETI•^•G 



May, the shortest period of Hfe-cycle observed is 49 days, viz., egg 

 7 days, larva 30 days, and pupa 12 days, the longest period taken by 

 some of the individuals out of the same lot being 71 days in which the 

 larval life only was extended to 48 days. In the cold weather from 

 November to January the larval stage has been observed to take about 

 2| months and the pupal stage about a month. 



As growth is very slow in the cold season the caterpillars are hardly 

 found in numbers in winter. With the spell of warm weather about 

 February their activity is observed in wheat and barley in wliich dry 

 ears appear. In March-April they are common in all the foodplants 

 mentioned above which happen to grow at the time and may cause 

 serious damage to maize. They occur in new shoots of sugarcane at 

 this time. But ordinarily they have not been observed to infest sugar- 

 cane in large numbers. From about June onwards they occur commonly 

 on rice and in very large numbers when rice is in ear about October- 

 November. 



From observations so far made S. inferens can be considered a pest 

 only of maize and rice. Normally it does not cause much damage to 

 the other foodplants mentioned. 



The female moth is capable of laying more than 400 eggs. One 

 laid 419 eggs in the Insectary. The eggs are thrust between the leaf- 

 sheaths and the stem in rows two to three deep. As many as 161 eggs 

 have been counted on a single plant. The egg is hemispherical in shape, 

 being about 0-7 mm. in diameter and having fine ridges on the surface, 

 the ridges running in regular order down the sides from the top. The 

 colour is creamy white, changing to brownish and ultimately to grey 

 before hatching. 



The newly-hatched larva is about 1-5 mm. long, pale yellow in colour 

 and has its head and cervical and anal plates dark brown. After the 

 first moult it assumes the characteristic appearance and colour seen in 

 older larvse. 



On hatching from the eggs the young caterpillars issue out of the 

 leaf-sheath and may disperse, going into neighbouring plants. They 

 may gnaw into the stems of young seedling plants either from the top 

 or from the side and bore in the central part causing " dead heart " 

 invariably. A\Tien they hatch on tall plants such as rice and wheat 

 in ear, most of them bore into the upper part of the stem and do not 

 disperse until they are somewhat grown. Many young caterpillars are 

 therefore found in individual plants with dry ears. The caterpillars 

 migrate from plant to plant, thus injuring many plants in the course 

 of their life. 



