Puant Lice INJuRING FOLIAGE AND FRUIT OF THE APPLE 711 
considerably for the other generations, tho in general it became shorter 
during the warmer part of the summer. 
The fourth generation produced the maximum average number of 
young (79.5), tho not at the maximum average daily production. The 
minimum average number of young (386) was produced by the winged 
females of the second generation. The average daily production is very 
interesting. It gradually increased from 1.85 in the case of stem mothers 
to 4.13 for the fifth generation, and then gradually declined to 1.77 for 
the thirteenth generation. 
The male-and-female-producing generation 
In the rearing cages the fourteenth generation proved to be the male- 
and-female-producing ‘generation. In their habits and activities the 
apterous viviparous females of this generation do not differ in any marked 
degree from the ordinary summer generations. They are sluggish, not 
showing any wandering propensities but depositing their young with 
quiet regularity. Owing to a series of accidents no complete records of 
the reproductive capacity of this generation were obtained. This is 
unfortunate, for such information would be highly instructive. 
Description of mature apterous female, fourteenth generation 
Length 1.92-2 mm.; width 1.04-1.2 mm.; cornicles 0.4 mm. long. 
The abdomen is dark green, with yellowish brown lines often forming 
a somewhat reticulate pattern on the dorsal surface; the head and the 
thorax are yellowish brown; the distal ends of the femora, the tibiae, and 
the antennae, and the tarsi, the cauda, and the cornicles, are black. The 
cornicles are cylindrical, and are tapering and slightly flanged at their 
tips. 
The oviparous females and the males 
The oviparous females and the males of Aphis pomz are very easily 
distinguished from individuals of the viviparous generations. They are 
wingless, are much smaller than the other generations, differ considerably 
in their general color, and show marked differences in their habits. 
In 1915 the oviparous females first reached maturity on October 1 
and egg deposition began on October 4 in the rearing cages. In 1914 
egg laying was first observed on October 6; in the field eggs were first 
observed a few days later. The egg-laying forms are active and do not 
