500 The American Naturalist. [June, 
THE GOLDEN-EYE OR LACE-WING FLY! 
By CLARENCE Moores WEED. 
Throughout the summer there may commonly be found 
upon the leaves of a great variety of plants, especially those 
infested by aphides of plant lice, groups of peculiar little verti- 
cal stalks tipped with small, oval, whitish bodies (Fig. 1 a). 
Should you be able to watch one of these groups for some time 
you would be likely to see a curious little larva hatch from 
each of the eggs—though the time of hatching is likely to vary, 
some emerging from the eggs considerably before the others. 
The larvee that have thus been cradled in the air are called 
aphis-lions, from their habit of feeding upon aphides. Soon 
after hatching they wander over the plant in search of prey, 
for which purpose almost any small insect will serve, but 
aphides generally form the principal item in the daily bill of 
fare. The aphis-lion has a formidable pair of jaws projecting 
forward from the head, so constructed that each jaw is a hol- 
low sucking tube as well as an organ for seizing and piercing 
the victim. 
Like other larve the aphis-lions cast their skins occasionally 
as they increase in size. They become fully developed after a 
few weeks, and are then nearly an inch long, and of the form 
shown in b and d of the figure. The different species vary con- 
siderably in color, but most are of more or less mottled shades 
of blue, brown, black and white. The presence of the suck- 
ing-tube in the jaw is explained when one examines the insect 
under the microscope, and finds that the mandible or jaw 
proper is grooved longitudinally on its inner surface, while the 
maxilla or secondary jaw is grooved longitudinally on its outer 
surface: these fit together so that the groves form a tube, 
through which the juices of the victims may be sucked into 
the stomach. 
The fully developed larva prepares for the change to the 
pupa by rolling itself together compactly, and then spinning 
1 From Stories of Insect Life, Grim & Co., 1897. 
