1918. | BASHAMBAR Das: The Aphididae of Lahore. 191 
It appears that the species originated in some colder regions in the hills. The 
life-history would be quite adapted to the conditions there. In autumn (about 
November) in such places the eggs are deposited and in this state the species tides 
over the severity of the cold winter. In spring these hatch and the insects reproduce 
throughout the summer and rainy season till the sexes arise again. . 
In the plains, probably on account of heredity, egg-forming females are seen 
about the same time, though the species has to suffer no inconvenience from the 
winter. Whether, as a provision against the summer, eggs are laid a second time is 
still to be discovered. 
The species falls a prey to numerous predaceous and parasitic insects that keep 
it in check in normal years. 
As the bodies of most of these Aphids touch each other when feeding, it makes 
them particularly liable to the attack of the Fungus “ Entomophthora aphidae,’’ which 
destroys them in large numbers. Fungus-killed Aphids turn yellow and soon shrivel 
to a brownish scale. 
Siphocoryne nymphaeae (Linn.). 
Synonym.—Rhophalosiphum nymphaeae, Koch. 
Hosts (in Lahore) :— 
(1) Lemna sp. (in Chhota Ravi). 
(2) Melumbium speciosum (Shalimar and Botanical gardens). 
(3) Scirpus lacustris (Shahdara). 
Numerous other aquatic plants have been reported as hosts of this very widely 
distributed species. 
Literature.—-Since Linnaeus’ time (1767) numerous writers on Aphids have 
figured, described or listed this semiaquatic insect. The monographs of Koch (pp. 
26, 44) and of Buckton (VI, p. 12) give accurate illustrated accounts. Essig (Pom. 
Coll. Jour. Entom., IV, 3, pp. 793-797, 1912) has lately furnished a morphological 
description with a fair summary of the previous literature. Patch (Maine Agric. 
Exp. Station Bull. 202, 1912) figures the antennae. Davis (Entom. News, p. 245, 
1910) and Cockerell (Science, p. 764, 1905) give useful accounts. ‘The insect has been 
listed in Lefroy’s Indian Insect Life, p. 747. 
Distinguishing characters —A rather large insect of a dark olive-green or reddish- 
brown colour (on Scirpus), often shining ; sitting singly or in pairs on floating Lemna 
fronds, or in large numbers on water-lily leaves, or in rows along the ventral surface 
of marshy Scirpus. A distinctive feature under the microscope is the clearly-marked 
polygonal areas on the skin, formed by the pores of wax-secreting glands; also the 
long, distally clavate cornicles; the spur is longer than III; about 17 sensoria on the 
alate antennae. 
The size, antennal lengths, sensoria and measurements of the cornicles and cauda 
of the Indian species agrees very well with the description of the insect by E. O. Essig 
from California. 
Miss Patch has published a figure of the antennae and cornicle, with notes on the 
size and antennal lengths, from Maine (Orono), which is different. The specimens 
