308 ATHALIA SPINARUM. 



The $ lias the two basal joints of the antennae entirely, and the other 

 joints beneath, pale luteous ; the face below and surrounding the 

 antennas and the inner edge of the eyes white. 



In the ? the antennee are often pale luteous or brownish on the 

 underside. 



Length 3 4 lines. 



Beadily known from the other species of the group 

 by the yellow markings on the mesonotum. 



The eggs are oval, whitish and semitransparent. 

 They are laid along the leaf margin on the underside 

 embedded in the epidermis. About 250 to 300 are 

 deposited by a single ? . According to Newport 

 sometimes only one egg may be laid on a leaf, but not 

 unfrequently as many as eight, ten, fifteen, or even 

 twenty, according to Curtis; when a number is de- 

 posited on the same leaf they are arranged along the 

 margin at irregular intervals. The same excellent 

 observer says that when only a few eggs are laid on 

 the leaf they are generally placed on the leaflet at the 

 base of the leaf and seldom at the apex. The fly does 

 not deposit her eggs indifferently on all the leaves of 

 the plant, but usually on the second set, " or four leaves 

 after the cotyledonous leaves," and never on the coty- 

 ledonous leaves themselves. Neither are they laid on 

 the inner or youngest leaves, which have their surfaces 

 rougher than the outer ones. 



According to most observers the eggs are invariably 

 laid in the hottest part of the day and when the sun 

 is shining. 



When first laid the egg is scarcely visible, there 

 being no trace of it apparent beyond a slight elevation 

 of the cuticle, and this is often so slight that it is only 

 by extracting the egg itself that its presence becomes 

 apparent. Within twenty-four hours the elevation has 

 increased while the egg has become more opaque. By 

 the second day it has still further increased, and the 

 depression in which the egg is situated widens so that 

 a free space equal to its own width surrounds it on 

 both sides. This continues to expand and the egg 

 bec'omes still more opaque, and the future larva is seen 



