The Cane Grubs of Australia. 13 



feeding by the end of that month and go deeper into the ground, possibly 

 entering cells (it is known that the larva enter cells as long as four 

 months before pupating), and hence are rarely ploughed out. 



In the relative abundance of the species this comes an easy second, 

 with 21-28 per cent, of the total. The larvae are distributed over the past 

 sixteen months as follows: — September 28, October 3, November 41, 

 December 90, January 69, February 129, March 371, April 188, May 

 187, June 169, August 16, September 7, October 16, November 16, 

 December 304. The numbers from forest and fallow lands and canefields 

 are — 77,545 yards plough furrows yield 496 larva3, forest and fallow 

 lands; 412,285 yards plough furrows yield 1,138 larvas, canefields; or 

 proportionately nearly 70 per cent, from the forest and fallow lands. 

 The figures from volcanic and clay and dark loam soils show a rather 

 greater proportion from the clay and dark loams. 



The unusually large emergence of beetles in the 1914-5 season w'as 

 succeeded by a corresponding large number of larva?. In December- 

 February, 1915-6 season, several cases came under notice where this 

 species was causing direct injury to the cane ; in one of these cases, in 

 new forest land, second year under cultivation, young first ratoons, the 

 cane was turning yellow and dying in some instances, and twelve stools 

 picked at random yielded the following larvte — 2, 0, 1, 0, 3, 4, 5, 5, 0, 

 2, 0, 3 ; in a second case, in old red volcanic soil, ratoon cane stools pulled 

 up yielded 8, 9, 4, 10, 6, 4, 8, and the roots of the plants showed direct 

 injury. 



The Pupa. 



Few larvffi were kept for rearing purposes, and little data is avail- 

 able as to pupation. Pup^e were taken from our rearing cages on 

 November 2nd, 12th, and 28th ; one that pupated on November 3rd 

 emerged on December 9th, giving the duration of the pupal stage as 

 36 days. 



The Adult. 



In confinement the first adult emerged on December 9th. 



In the 1914-5 season vast numbers emerged ; the first emergence was 

 recorded on December 28th, and during the week following thousands 

 were flying and swarming at dusk in canefields. The flight commenced 

 earlier than with alhohirta, and lasted for about twenty minutes; after- 

 ward mated pairs were found attached to cane leaves, but the great 

 majority had betaken themselves to the neighbouring forest where the 

 humming of their flight was audible among the tree tops until 8 p.m. 

 when observations were discontinued. Later, on Januarj^ 23rd-31st, 

 another large emergence occurred, the beetles being present in the same 

 fields as during the earlier emergence, and enormous numbers were 

 swarming over the grass plots in the toAvnship, hundreds of mated pairs 

 being observed clinging to fence posts, Avire fencing, low shrubs, &c. ; 

 after the end of January only a few beetles were present, and by 

 February 10th they had disappeared. An adult was ploughed up on 

 February 23rd, another on JMarch 10th. In the 1915-6 season, the species 

 was not nearly so plentiful ; a few Avere first observed on December 8th, 

 and again on the 10th, emergence being general by the 15th. In all the 

 swarming noticed, mating occurred almost invariably within three feet of 

 the ground, and when mating in company with rothei and No. 215, these 

 latter species were always at a greater height. 



