LIFE HISTORY. 43 
The second undoubted record is of material sent to Doctor Howard 
for determination by Dr. James Fletcher, entomologist of the Canadian 
Central Experimental Farm at Ottawa, who reported that the infested 
oranges sent had been forwarded to him from British Columbia and had 
been imported from Japan. These oranges, evidently of a mandarin or 
tangerine type, showed undoubted infestation with the San Jose scale. 
Jt is therefore evident that this scale insect may occasional!) infest 
the orange, but the long coexistence of the San Jose scale and orange 
culture in southern California would seem to indicate the practical 
immunity of the orange tree from this scale pest. An earlier record 
of the San Jose scale on a citrus plant, b} r Mr. Cockerell, has aiwa}^s 
been under the question of a misidentitication of the food plant. 
LIFE HISTORY. 
In common with all the armored scales, the life round of this insect, 
with the exception of a few hours of active larval existence and an 
equally brief winged existence in the case of the mature male, is past 
under the protection of a waxy scale. This scale covering conceals 
the real insect beneath and prevents an}^ easy observation or study of 
its life histoiy. The San Jose scale has been under most careful 
observation b} r Mr. Pergande on potted plants in the insectaiy, and its 
history, which has hitherto been very imperfectly worked out, has been 
thorol} 7 and carefully elaborated. 
The winter is past by the insects in a half-grown condition under 
small black protecting scales, mere points, just visible to the naked 
e}^e. The male scales are normally vastly in excess of the females, 
often representing 95 or more per cent. Early in April, in this lati- 
tude, the males transform to pupa? and emerge, and this gives the 
appearance of a sudden death of the great majority of these overwin- 
tered insects on the bark, and has led to some confusion in interpret- 
ing the effect of washes. The females at this period have arrived 
at the stage of impregnation, and the delicate two-winged males dis- 
appear after a few days. About a month later, varying with the cli- 
mate, the overwintered females come to full maturity and begin to 
give birth to a new generation, continuing to produce young for a 
period of upward of six weeks, when they reach the limit of produc- 
tion of young and perish. 
The adult female gives birth immediate^ to living 3-oung, differing 
in this respect from most other scale insects. Ordinarily eggs are 
deposited beneath the scale, which in the course of a longer or shorter 
time hatch, and the } T oung larvae make their escape and migrate to 
different parts of the plant. In the case of some scale insects the 
female tills its scale with eggs in the fall and perishes, the eggs win- 
tering over and hatching the following spring. In others the insect 
