14 Farmers’ Bulletin 1261 : 
SEASONAL HISTORY AND DEVELOPMENT. 
During the dormant season of the avocado the pyriform scale is 
quite inactive. Infested trees during December, January, and Feb- 
ruary possess foliage 
covered with the fe- 
male scales in a half- 
grown condition, ma- 
turity taking place 
in the spring. In 
March the female 
scales form cottony 
margins, and ulti- 
mately hundreds of 
eges will be pro- 
duced within these 
cottony masses in 
process of formation 
beneath the scales. 
During April the 
males emerge from 
those scales which 
have no evidence of 
cottony secretions. 
The writer has ob- 
served at. various 
times in southern 
Florida males in 
great numbers dur- 
ing the middle and 
latter part of April. 
Evidently fertiliza- 
tion takes place at 
this time. The cot- 
tony masses in May 
are really little bags 
packed _ full of 
minute, yellowish, 
Fic. 9.—The pyriform scale: Lower surface of avocado ’ b c TI 
ner: or “° oval bodies. 1ese 
leaf, showing adult scales with characteristic white 
fringe; also young scales scattered among them, ap- are the eggs, and the 
pearing as mere specks. white covering is 
merely an egg sac consisting of waxen filaments excreted from the 
lower surface of the scale. The eggs commence to hatch in great 
numbers during May, when rows of young scales may be seen upon 
the under surface along the lateral veins and ribs of the leaves. 
tha i in icatie 
