10 Some Lepidopterous Pests New to Sugar Cane in Queensland. 
Habitat. 
Widely distributed in Australia from Port Darwin to Sydney; 
being found also in West Africa and throughout the Oriental region. 
Its occurrence in Queensland as a cane-pest in 1916 may, I think, 
be attributed primarily to abnormal climatic conditions. The trying 
drought experienced during 1914 to 1915 terminated about December of 
the latter year, the rainfall registered for that month and January 1916 
being collectively 48-1 in., as against 25-83, the average for these two 
months in the Cairns district during the preceding twenty-seven years. 
The caterpillars appeared about seven weeks subsequent to this down- 
pour, towards the end of March, and by April had attained sufficient size 
to work appreciable damage to the cane. 
It seems that very wet conditions apparently favour the increase of 
an allied noctuid, Laphygma frugiperda S. & A. (‘‘Southern Grass 
Worm’’). 
In Porto Rico, for instance, the larve of this moth*t in company 
with those of Mocis repanda F., are stated by H. T. Jones to have 
‘‘oceurred during 1912 in enormous numbers at Rio Pedras over an 
area that had been overflowed during the previous month.’’ Among the 
factors assigned by him as possibly responsible for serious infestations 
of this nature may be mentioned—(1) migration of the species owing 
to unsuitable conditions, as lack of food, abundant water, &c¢., and (2) 
transportal by floods of the eggs and caterpillars amongst vegetable 
débris, &¢., which being washed from watersheds to low-lying ground 
would naturally tend to accumulate on flats hable to temporary flooding. 
In our own ease I am inclined to believe that the drought conditions 
already mentioned may have operated as a decided natural check to the 
inerease of various parasitic insect enemies of Mocis frugalis, thus 
enabling most of the first-brood caterpillars to attain the moth stage. 
An abundant food supply induced by copious rains insured the rapid 
development of these larva, causing also the resultant brood of moths 
to meet with conditions eminently favourable to the increase of their 
offspring. It was the enormously large number of eggs deposited by 
this second brood that gave rise to the July infestation, but apparently 
by that time the balance of nature had been practically restored, as the 
following brood of larvee occurring in the same locality during June (two 
months later) was very small. On this occasion, however, they were 
destroying plant cane growing in a paddock free from weeds of any kind, 
a fact which although trivial is not without significance, since it furnishes 
another illustration of the readiness with which certain insects will 
acquire a hking for cultivated plants. 
? 
Mocis frugalis—termed in America ‘‘White Nile Army Worm’’— 
attacks sugar-cane in Brazil, where it has been known for the past twelve 
*««Some Notes on Laphygma frugiperda 8S. & A. in Porto Rieo,’’ Journal of 
Economie Entomology, vol. 6, p. 230, April 1913. 
