BABITS AND LIFH HISTORY. 
3!) 
The adult female gives birth immediately to living young, differing 
in this respect from most other scale insects. Ordinarily eggs are de- 
posited beneath the scale, which in the course of a longer or shorter 
time hatch, and the young larvae make their escape and migrate to 
different parts of the plant. En the case of some scale insects the 
female fills its scale with eggs in the fall and perishes, the eggs winter- 
ing over and hatching the following spring. In others the insect hiber- 
nates in the nearly mature condition, as does the San Jose scale, and 
deposits eggs in the spring or early summer. The viviparous habit. 
or the giving birth to the living young, i>ossessed by the San Jose 
scale, finds a parallel in many other insects and frequently in plant- 
lice. In the case of the San Jose scale the eggs are fairly well formed. 
l4^U* 
Fig. 3.— Younglarva and developing >cale: a. ventral view of larva, showing packing beak with 
setae separated, with enlarged tarsal claw at right; b, dorsal view of same, somewhat contracted, with 
the first waxy filaments appearing; c, dorsal and lateral views of same, still more contracted, illus- 
trating further development of wax secretion; </. later stage of same, dorsal and lateral views show- 
ing matting of wax secretions and fust form of young scale— all greatly enlarged. (Original.) 
a few at a time, within the body of the mother. What takes the place 
of the eggshell consists of a very delicate and thin membrane— the 
amnion — which incloses the developing larvae and which at the moment 
of birth is cast off. and remains attached to or partly within the oviduct. 
The amnion is probably pushed out by the next larva in turn. The 
difference between this mode of birth and the ordinary method through 
the medium of tine eggs is simply that what corresponds with tin 
is retained by the female until the larva is developed, instead of develop- 
ment of the larva progressing after the egg leaves the parent. 
The emergence of the young from the female over a period of six weeks 
leads to a very confusing intermingling of generations and renders it 
