No. 3.] Sugarcane. 175 



Swinhoe, Cat. Moths, India, p. 684, n. 4655 (1889) ; Alcock, Ind. M us. Notes, 

 vol. v, p. 43, pi. vi, figs. 1, female twice enlarged ; 2, section of sugarcane* 

 showing cocoon U900). 



This insect has only once been reported to damage sugarcane, 

 the caterpillar having been sent down to the Indian Museum, 

 Calcutta, from Kushtea, the moths bred, and the species figured 

 in "Indian Museum Notes," vol, v. In May, igoi, Mr. H. Thorp of 

 Sikta, Betteah, on the Nepal frontier, sent some caterpillars to 

 the Museum, which proved to be this species. 



In June, 1901, I visited Sikta, and found that quite fifty per 

 cent, of the shoots of the " khari " variety of cane grown by 

 Mr. Thorp was bored by this insect ; the " reonda " variety of cane 

 was also badly affected. The " khari " cane was obtained from the 

 Burdvvan Experimental Farm. The symptoms of an affected cane 

 are very similar to those attacked by Chilo simplex^ Butler, a '.' dead 

 heart " is always present if the larva has been in the cane some while, 

 but the presence of S. auriflua can always be told by the base of 

 the leaves from the growing point of the cane having a series of holes 

 across each leaf at right- angles to the length of the leaf bored with 

 a parallel row, which were made by the young larva when it first 

 penetrated into the cane after hatching ; these holes seem never to 

 be present in a shoot attacked by C. simplex. As a rule the leaves 

 are bent backward and fall over at the point of perforation, so an 

 affected cane can at once be detected by this feature as well as by 

 the l< dead heart/' The line of holes arise from the fact that the larva 

 penetrates into the heart of the cane when the leaves are tightly 

 rolled up before they unfold, so that each leaf is penetrated in 

 several places. The falling over of the leaves is due to the wind 

 acting on a weakened spot. In all other respects the injury done 

 by this insect is similar to that of C. simplex ; the larva bores 

 right down the centre of the shoot, the inside turns black and 

 rotten, and harbours many insects which feed on the decayed mass 

 Each attacked shoot stops growing, the growing point being killed- 

 When full-grown the larva has nearly reached the root of the cane j 

 it bores a hole at right-angles to the tunnel in which it has hitherto 

 lived to the outside of the cane, lines this hole with silk, and fits a neat 

 lid or operculum across the hole of exit, through which the moth on 

 emergence from the chrysalis leaves the cane. The larva then 

 retreats about an inch up its tunnel, spins a flimsy silk cocoon of 

 white silk, and turns to a pupa, its head downwards and towards the 

 hole of exit. A light placed out in the fields over a tray of 

 molasses only produced one moth, so this trap does not appear to be 

 very effective, probably the moths fly but little, especially in windy 



N2 



