t>i5 



The Cane Grubs of Australia. 



Tryon states that the larva of D. fonnosa " may attain its maximum 

 development within a fortnight or less." We have not gathered any 

 data on this subject, but that the duration of the stage is short is shown 

 by the follo^dng record: — On September 27th five Stage III. larvge of 

 Lcpidiota caudata were placed in a rearing cage sunken in earth, and 

 were then of course quite healthy; the cage was opened on November 

 16th, finding 1 pupa, 2 dead larvjv, and 2 cocoons with Dielis fonnosa 

 pupa?, attached to the remaining larval remains in the pupating cells; 

 thus the Dielis had attained this stage of developmejit within 50 days. 

 Also, as in two cases mentioned above, paralyzed larva" remained alive 

 for less than four weeks, the parasite larva probably attains its full size 

 within that time. 



Four hosts are kno^\m — ^viz., Lepidiota rothei, L. alholiirta, L. 

 caudata, and Anoplognathus hoisduvali. 



Larvfe have been recorded as follows: — 14th June, D. formosa, 

 taken from cocoons; 28th May, full-gro^^^l larva attached to Stage III. 

 Anoplognathus, spun cocoon within twelve hours: 27th October, full- 

 grown Discolia soror on host, ]| feet deep in sand, spun cocoon on 

 folloAving day ; 10th September, full-grown larva on Stage III. Lepidiota 

 alhohirta; 14th September, full-grown larva on Stage III. Anoplog- 

 nathus; 19th August, small larva on Stage III. Anoplognathus. 



The earliest record of a cocoon is that of a Caynpsomeris radula 

 attached to Stage III. L. alhohirta on 27th April. The length of the 

 pupal stage, or rather the period spent in the cocoon, varies considerably, 

 and sometimes this may last for four or five months. A cocoon of 



C. radula found on April 27th emerged on July 22nd, or 86 days; a 



D. soror cocoon spun on October 28th emerged on December 7th, or 40 

 days ; another cocoon of D. soror found on June 29th emerged November 

 11th, or 135 days, and a third found on August 19th emerged December 

 11th, or 114 days. The majority of the pupa? emerge during November 

 and December, and there is also a considerable emergence in June and 

 July, which would appear to agree with Tryon 's conclusion that there 

 are two broods in the year. Adults are seen in smaller or greater num- 

 bers throughout the year; Campsonicris radula has been captured in 

 numbers in June and October, and Discolia soror swarms plentifully 

 in November on shrubs on the banks of the IMulgrave River. A i'emale 

 Dielis formosa was noticed standing over a paralyzed Stage III. Lepidiota 

 alhohirta in canefield May 2'6th. 



A cocoon containing a larva found in a canefield September 3rd was 

 kept in confinement; the larva is still alive and not pupated now, on 

 February 14th; that is, it has remained in this dormant state for 364 

 days. 



During July, August, and September, numerous Stage III larvfp of 

 Lepidiota rothei were placed in our rearing cages ; the cages were opened 

 in December, when it Avas found that some of the larvie had succumbed 

 to Scoliid parasites, of which nine were obtained. These all produced 

 male Dielis formosa, and from this record inter(^sting deductions can be 

 made. The male Dielis formosa is much smaller than the female; also 

 rothei is a small larva, and would not furnish enough sustenance to 

 produce the large female Scoliids. Hence it is probable that all Dielis 

 formosa obtained from rothei would be males ; then are males ever bred 



