381 
mally infests the upper surface of the leaves, but also occurs on the fruit 
of the Orange. Morgan, as quoted above, records it from Dictyosper- 
mum. 
HABITS AND HABITAT. 
The Rufous Seale is extremely abundant at Kingston; but at Mon- 
eague I found it morerarely; and at Mandeville, nearly 2,000 feet above 
sea level, it was not to be seen, and the oranges and cocoanuts, so far 
as observed, were free from scales. This immunity in the mountain re- 
gions has been attributed,* no doubt correctly, to the damp and com- 
parative coolness, a hot and relatively dry climate being necessary for 
their favorable existence. 
It is also to be observed that while some palms, on which there are 
no other Diaspine, are so badly infested that the surfaces of the leaves 
aré in places absolutely covered by scales; others, which support Jsch- 
naspis, Aspidiotus palme (nu. sp., Ckll. MS.), A. jicus, Diaspis, or Chio- 
naspis, are less preyed upon by A. articulatus. It is not always a 
question of want of room, as some of these species do not cover the 
leaves in the manner of the Rufous Scale, but there seems to be a form of 
natural selection at work, so that when one species has obtained a foot- 
ing on any given tree, another has difficulty is establishing itself. This 
may serve to account for the fact that although A. articulatus is common 
in Barbados, and Cocoanut is one of its known food-plants, some badly 
infested leaves of Cocoanut from there show no A. articulatus, but quite 
different species. In Kingston, some palms are, one might say, smoth- 
ered in A. articulatus; while others, which support different kinds in 
addition, are on the whole less severely attacked, notwithstanding the 
greater number of species infesting them. In this way, it seems possi- 
ble that a species of Coccidee might be indirectly beneficial by keeping 
off another species more destructive than itself. 
REMEDIES. 
The remedies usually employed for other species of Diaspine will be 
appropriate for A. articulatus; but as it infests so great a variety of 
plants it will be more difficult to control than others, which, like A. 
palme,t are apparently confined to one. I learn from Prof. Riley that 
it has never yet been detected in the United States, and as it is a very 
undesirable insect, due measures should be taken in order that it may 
not be accidently imported. Whether it exists throughout the West 
Indies remains to be ascertained. From its occurrence both in Barba- 
dos and Jamaica, this might be expected, but it must be remembered 
*See Journ. Inst. Jamaica, Vol. 1, p. 48, (1892). 
t The difference of taste between some closely allied species of insects is very re- 
markable. A. palme seems confined to Cocoanut, but A. rapax, a very close ally, 
lives on many different plants. In Lepidoptera Deilephila lineata is almost omnivor- 
ous, whereas D. euphorbie eats one species of Euphorbia only, I believe. 
771—No. 11 3 
