90 
BEITISH APHIDESe 
the winged condition is that usually assumed by the 
male sex. 
The males and oviparous females often in an infe- 
rior degree exhibit the peculiar characteristics of the 
genus under which they are included. So far as the 
oviparous females are concernedj they seem to furnish 
marks of a degraded metamorphosis, just as we observe 
in the imperfect development of the apterous females of 
some Lepidoptera, like Orgyia antiqiia and Cheimatohia 
hrumata. In appearance the male usually precedes 
the female by a few days. 
It has been already remarked that temperature alone 
does not cause the appearance of the males, for some 
occur in the warm days of September. The heat of 
summer, on the other hand, does not change the 
oviparous character of Chermes and like genera. 
THE OVIPAROUS FEMALE, 
This sex is uniformly apterous amongst the Aphi- 
dinse, but it occurs both apterous and alate amongst 
the Ohermesin^ and allied genera. In Aphis proper 
the oviparous females rarely attain the full size of the 
viviparous females, but they are characterised by more 
robust bodies and stouter limbs. The hindtibise often 
are expanded into narrow flattened plates, which pro- 
bably assist the insects in glueing their ova to plants and 
bark fissures. Some oviparous forms deviate a good 
deal from the shape of thelarvse andpossessmuch shorter 
antennse, which organs, nevertheless, may contain their 
full number of joints. Usually the insects are obscurely 
coloured and do not set forth the ornamental bands 
and spots to be seen in the males. The absence of 
stemmata or ocelli indicates their inactive habits and 
small locomotive powers. The abdomen is bulky, 
usually from the presence of from five to seven large 
eggs, which shine through the integument as oval 
yellow masses. Besides these mature ova, other smaller 
