Lepidiota frenchi Blackburn. 



This species was named by the late Rev. Canon Blackburn, and the 

 description appeared in the Transactions of the Royal Society of South 

 Australia, vol. xxxvi, 1912. The type locality was given as "Queensland 

 (Cairns) ; male from Mr. French, female from Mr. Lea." 



As to the distribution of this species, Girault andDodd (66) included 

 Mossman, Cooktown, and Babinda. But liy carefully breeding out the 

 grul)s Mr. Dodd (91) found that those from Cooktown were Lepidiota 

 No. 683, a species later named consohrhia by Girault; and the Babinda 

 grubs proved to be Lepidiota caudata Blackburn. Mr. Jarvis, however, 

 probably overlooked these data, for he (99) based his conclusions upon 

 the unverified records published ]\v Girault and Dodd. Subsequent 

 observations go to show that this species belongs essentially to the open 

 forest country, favouring areas well supplied with the native grasses : 

 it has never iDeeu collected in the densely timbered scrub lands. Then. 

 too, as far as we have been able to observe this species occurs only at 

 Mossman. outside of the Cairns district, where its chief centre of action 

 is about Gordonvale. 



IMPORTANCE AND NATURE OP INJURY. 



Though the range of this species is apparently limited, the individuals 

 sometimes emerge in tremendous numbers, and their offspring, the grubs, 

 frequently do considerable damage to sugar-cane. Indeed, in their range, 

 they are considered almost as destructive as the larger greybacked species. 

 This is largely due to the fact that the grubs live almost two years in 

 the soil, the very destructive third stage requiring full.v a year to mature. 

 Furthermore, these large grubs are able to start activities on the cane- 

 roots in August or September, several months before the eggs of the 

 greybacks are laid ; hence their work at this season is particularly 

 noticeable, especially on the late-planted crop. 



My first experience with this pest was in a first ratoon crop of Badila 

 near Gordonvale, in November 1917. As many as twenty-five large 

 stage III grubs were found under a stool, near the grassy roadside, while 

 further back in the field the average per stool was only five to eight. 

 The infestation appeared to be in patches, a chain or so in extent, and 

 these were more prevalent near the grassy borders of the field. About 

 the same time I discovered plant cane suffering in a similar manner on 

 several other farms near Gordonvale. In each case there was the same 

 spotted appearance in the fields, comparatively small areas here and there 

 being practically killed out, whilst adjoining cane "was nice and green 

 The in.jury was particularly bad in a field where grass had been ploughed 

 out preparatory to planting the croj). The grubs had eaten off' all the 

 roots of the young plants, and in some cases had bored right into the old 

 seed-stalk, where we found them at work; in other instances they had cut 

 off the young shoots, just as is the habit of the greybacks. 



November, 1918, I found this species giving considerable trouble 

 at ]\Iossman. One ratoon field at the edge of town, though yellowed in 

 patches by them, was not killed out; this was apparentl.v due to the fact 

 that the grubs were more abundant luider bunches of grass that grew in 

 the centres than they were in the cane itself. At ]\!o\vl)ray, too. in that 

 district, I found this pest; it had killed out plant cane wherever it 

 occurred on high spots in the field; moreover, cane in tlie low places was 



