80 DESTRUCTIVE INSECTS OF VICTORIA : 



have not been reared within the cultivated area from 

 entering the crop, the open trenches which should encircle 

 the paddock should be about 18 inches wide by about the 

 same depth, with perpendicular sides as before described. 

 If found necessary to dig these trendies for the purpose 

 of keeping the pest as much as possible in hand, the land 

 should be so laid out as to admit of main trenches, with 

 reticulations, throughout the field, which would have the 

 effect of atfordino' the means for the destruction of the 

 greater number of the caterpillars which were in the crop. 

 On grass lands where it is tolerably clear of trees, stumps, 

 or stones, the brush-harrow will work wonders, as these 

 are cheaply and easily made by bolting four pieces of 

 strong hardwood quartering together so as to form a 

 square, with a few saplings crossways across the frame, 

 and into which rough branches, as mallee boughs, hakea, 

 bull-oak, &c., &c., could be twisted, and with a fairly 

 fast horse it is wonderful what can be done with these 

 harrows in a day. During the past year, 1899, it was 

 noticed by Mr. C. C. Brittlebank, who first brought the 

 matter under notice, that the caterjoiDars in the Bacchus 

 Marsh district were attacked by some disease which prac- 

 tically exterminated the caterpillars of these noctuid 

 moths in this district, which is a large and important one, 

 and where serious damage to the crops had previously 

 occurred. Being desirous of obtaining some of the 

 fungus-infected caterpillars, I sent my assistant, Mr. 

 C. French, jun., to collect some specimens, and he reports 

 as follows : — " Caterpillars attacked by the fungus were 

 noticed on the slopes of the hills leading down to the 

 Werribee River, at Myrniong, near Bacchus Marsh. The 

 damage done by these caterpillars to the valuable native 

 grasses, such as the ' Wallaby Grass ' (Danthonia) and 

 the 'Kangaroo Grass' (Themeda), &c., was very striking, 

 large patches of ground appearing as if a mob of sheep 

 had been camped thereon for some time, and having eaten 

 all the grass and trampled stalks down it thus presented 

 a very barren appearance. A few yards nearer the river 



