Notes on Insects Damaging Sugar Cane in Queensland. 



This pest was observed by the writer dui-ing- Oeto1)(n'. 1014. damag- 

 iug ratoou and plant cane by tininellino- and killing the young suckers. 

 Upon cutting open an affected slioot the centre was seen to be hollow, 

 often down to the roots, and more or less choked with excreta ; or else 

 partly transformed into a brown evil-smelling mass of decomposing 

 fibres. 



In September, when growth is just commencing, a single cater- 

 pillar is able to kill many shoots ; in some cases stools had lost over a 

 dozen ; this, however, was doubtless due to the presence of more than 

 one borer. Injurious symptoms are very conspicuous in the field, as the 

 central leaves of affected plants, being at once killed, turn brown in a 

 few days. 



Description of Larva. 



General colour light-purplish, blotched indistinctly with dull white. 

 Head bright to very dark red. Prothoracic collar light-yellow. Dorsal 

 surface of 2nd and 8rd thoracic segments deeply wrinkled. Abdominal 

 segments 1 to 8, with four black dots on dorsal area, each encircled by a 

 whitish ring, the anterior pair closer together than the others, except 

 on 8th segment, on which they are wider apart than the posterior pair ; 

 9th segment with a row of six large smoky blotches close to posterior 

 margin. Anal segment light-yellow, shining, with 8 dull yellow hairs 

 arranged in two transverse rows, each hair being encircled by a tiny 

 black ring. Spiracles surrounded by four very irregular unequal sized 

 smoky blotches larger on 8th abdominal segment. All dots and blotches 

 mark the site of a single short brown hair. Ventral surface dirty white, 

 prolegs and sides of claspers yellow. Length, 25 mm. to SS mm. (1 to 

 11/2 inches). The larva when disturbed invariably seeks the bottom of its 

 tunnel, making no attempt to vacate it unless the shoot be sectioned 

 lengthwise, when it drops hastily to the ground and remains motionless. 

 When fully grown it pupates either in the centre of injured suckers 

 amongst moist excreta, or outside close to the ground against the bases 

 of dead canes, or under withered leaf-.sheaths and debris previously 

 webbed together to afford temporary protection. 



Description of Pupa. 



Reddish-yellow, darker on head, back, and anterior edges of seg- 

 ments. Head-end abruptly rounded bluntly. Extremity of anal segment 

 very dark red, flattened, with two short curved hooks turned up at an 

 angle towards dorsal surface (see Plate I., Fig. A), and near them a 

 short longitudinal groove on ventral area. Abdominal segments punc- 

 tured near anterior margins, particularly on their dorsal surfaces. 

 Length, 19 mm. The pupal stage of first brood in November occupies 

 twelve days under an average shade temperature of 77 deg. F. 



