206 Memoirs of the Indian Museum. VOA 
Natural enemies.—Chilomeles sexmaculata and Coccinella septempunctata in the 
larval and imago stage destroy large numbers of this Aphid. All the common 
Syrphids actively deposit their white eggs among them, and their blind larvae were 
noticed sucking hundreds of them dry every day. An Aphidius is sometimes bred 
from among colonies of this Aphid but is never abundant. 
_ À curious disease attacks them, possibly of a Fungoid nature, which kills almost 
all of them at once. The attack seems to be rather sudden, and one might almost 
unexpectedly find at any time the under sides of leaves full of reddish-brown or later 
darkish-brown shrivelled-up skins in place of living yellow Aphids. It has often 
been noticed to appear specially after a very hot day. The heat may have something 
to do with it, as the outward appearance of the dead specimens is not very different 
to that of a scorched insect. The Aphids remain attached to the leaves for a long 
time. 
Life-history. — This Aphid can live through the winter in the parthenogenetic state, 
but probably the sexes are produced before the winter, though none were collected. 
Every year in February, March and April the leaves and flowers of Hoya viridis are 
covered over with this Aphid in thousands. In September again the case is the 
same. Any of the above mentioned hosts may be similarly attacked. 
Aphis sacchari (Zehntner). 
Name and host.—This plant-louse was first noticed on sugar-cane in Java and 
named after its host (Arch. Jav. Suiker-industrie, DI. IX, p. 674, 1901). The original 
. description is in Dutch. Y 
In India the insect has never so far been collected from Saccharum officinarum 
(sugar-cane), but is here certainly a Sorghum Aphis. The only other plant known as 
its host in this country is Panicum colore. 
Distinguishing characters.—It is found on the under side of leaves of Sorghum 
vulgare (juar or chari) in thick patches, and excretes ““honey-dew’’ so profusely as 
to blacken all the leaves. The fungus that forms sooty layers, scales off in thin flakes 
from the dry leaves. 
The insect is almond-yellow or pink in colour with a thick, stout body with small 
black cornicles ; there is a pattern on the abdomen of the alate female, and from ten 
antennal articles are : I o'ı mm., II 0°08 mm., III 0°36 mm., IV 0:28 mm., V 0:25 mm., VI o'I mm., 
VII 0:47 mm. ‘Thus the 5th joint is distinctly shorter than the 4th, exactly as in our Asclepiad Aphis! 
The difference between A. neri and A. asclepiadis, as mentioned by Mr. Theobald, can therefore hardly 
be correct. | 
As has already been pointed out by Mr. Das the description of the Oleander Aphis, as given by 
Essig, agrees fairly well with that of our Asclepiad insect. It remains, however, a very astonishing fact 
that in tropical regions this aphis should only show a partiality towards Asclepiadae and leave the 
oleander uninfested. Still more curious is the fact that, after Mr. Theobald, Aphis asclepiadis should 
attack Salix too. Only biological experiments will be able to definitively settle whether the Aphids on 
Asclepiads, oleander and willow are to be regarded as one species or not. Until this question is 
solved, I think it best to follow Schouteden and call our Asclepiad Aphis Aphis nerii, Boyer. P.v.d.G.]. 
