744 
rhynchota. 
with long straight antennae, small compound eyes, and long thread-like 
mouthparts extruded from a short proboscis. The thorax and abdomen 
Fig. 517— Rhopalosiphum dianthi. (I. M. N.) 
are robust, the latter having a pair of 4 siphons 5 on the dorsal surface ; 
there is a short tail-like structure on the lower surface, the Cauda. The 
legs are long and the insect walks slowly. Wings are long, with few veins, 
usually hyaline with pearly reflections. Wingless individuals are very 
common and occur with winged ones. The life-history presents peculiar 
features, adaptations to the 4 parasitic ’ mode of life of these insects. 
The females are, as a general rule, parthenogenetic, producing eggs and 
young without the intervention of a male. Generally young are pro¬ 
duced which are females ; the development may be very rapid, there 
being but few moults, and after the lapse of three days the female often 
commences producing living young, which will after the lapse of three 
days in turn produce young. This occurs normally in our common 
aphides which live on mustard, wheat, and cotton. 
In temperate climates, there is often a brood of both sexes, of which 
the females produce eggs ; this brood normally occurs before the winter 
and the eggs survive the cold winter. This has not been shown to occur 
in India and there is as yet no evidence that such likely is to occur; some 
