10 The Cane Grubs of Australia. 



During the past sixteen months collecting by following ploughs 

 resulted as follows : — September li-l, October 25, November 1, December 

 0, January 20. February 299, March 707, April 600, :\Iay 453, June 192, 

 August 23, September-December 0. The figures for volcanic and dark 

 and light loam soils are nearly equal. 



The species was not abnormally abundant in 1915, and on the whole 

 canefields were fairly free from its depredations, but there were instances 

 of unusually severe attacks on individual farms. For example, the e.state 

 of Greenliiils, where the open volcanic soils seem to give ideal conditions 

 for the larva^ suffered to an extreme extent, and hundreds of acre.s of 

 cane was completely killed ; in the jungle lands of the Babinda iNIill area 

 serious damage was caused in several cases. 



Digging in soil in jungle, Babinda, 21st September, 1914, produced 

 a single Stage III. larva. 



The Pupa. 



In 1914 the majority of the larvie pupated during September; in 

 1915 pupge were not uncommon during the latter half of August. An 

 exceptional record is of a larva placed in confinement on April 13th, that 

 pupated on Jlay 30th. September and October, 1914, were remarkable for 

 the large number of pupa.^ ploughed up ; thus in September 140 pupae 

 were obtained from 86,480 yards plough furrows, in October 331 pup^e 

 were obtained from 110,840 yards plough furrows. The comparative 

 shallow depth at which the pupas were found (less than eight inches) 

 may be accounted for by the frequent showers during August and 

 September keeping the soil moist. 



Many pupse taken from canefields on September 9th commenced 

 emerging on October 2nd and continued until November 2nd, giving the 

 maximum duration of the pupal stage as 54 days. The last pupa to 

 emerge was on November 20th. 



The Adult. 



In 3914 the first unemerged adult was ploughed out on September 

 16th in red volcanic canefield, but further specimens were not obtained 

 under October 2nd, and by October 25th were not common ; in 1915, an 

 adult was ploughed out on July 20th, again on August 21st, and were 

 rather plentiful by the end of September. 



There appears to have been no general emergence in 1914, this being 

 spread over several wrecks. The first beetle flew to light on November 

 13th; on November 17th a few were noticed in a banana plantation on 

 the banks of the Mulgrave River, and within the next weeks were 

 plentiful in this locality (within the immediate vicinity of Gordonvale 

 emergence occurs here first, that is from the alluvial loam canefields on 

 the right bank of the ]\Iulgrave River) ; on December 13th occurred the 

 first emergence of any magnitude, and subsequently freshly emerged 

 beetles were noted until nearly the end of Januarj^ ; on February 2nd a 

 considerable emergence was reported from Aloomba; by February 16th 

 beetles were very scarce, and the the last seen was on the 20th. On 

 January 28th ploughing in a dark volcanic canefield yielded adults, ova, 

 Stage I. and II. larva?, and on February 20th ploughing in yellow clay 

 loam fallow land produced an adult, Stage I., II., and III. larva^. 



In 1915 an emergence occurred from the alluvial loam canefields on 

 November 19th, a general emergence took place on December 4th except 



