INSECT ENEMIES. 127 
The Aphis-lions and the Lace-winged flies produce larvee 
which destroy them in abundance. Myriads of aphides 
are destroyed by Lady-birds and their larve. There are 
nearly a hundred species of Lady-birds, all of which are 
our helpers. I have found the large black ant of great 
service. They concentrate on limbs infested with lice, 
and clean them off. I count each nest of ants worth a 
dollar a year as insecticides. 
The Syrphus flies (Syrphus politus, Say) lay one egg 
in a group of plant lice, which hatches out a footless, 
eyeless, flattened, wrinkled, green and purple maggot. 
Their bodies are supple, and their mouths are provided 
with a triple-pointed dart, with which they pierce the 
aphides, and suck them dry. 
A black aphis appears some years in considerable num- 
bers on my quince cuttings, just in time to destroy open- 
ing buds. Later I have found it in large numbers on 
the young shoots of growing trees. I have not yet 
determined with certainty its position in the aphis 
family. 
18. Katy-pID, THE BROAD-WINGED Katy-p1IpD (Cyr- 
tophyllus concavus,Say; Platyphyllum concavum, Harris). 
—Platyphyllum means a broad wing, and is used to dis- 
tinguish this from the Southern Katy-did, which belongs 
to the genus Phylloptera. tis a green grasshopper of the 
order Orthoptera, and derives its common name from the 
note of the male, which is produced bya kind of taboret. 
The triangular overlapping part of each wing-cover forms 
a strong half-oval frame, in which a thin, transparent 
membrane is stretched. The friction of the taboret 
frames against. each other when the wing-covers are 
opened and shut, produces several distinct notes closely 
resembling articulate sounds, and corresponding with 
the number of times the wing-covers are opened and 
shut. In the stillness of the night these notes may be 
heard a long distance, as rival notes answer from adjacent 
