THE BIOLOGY OF THE CHRYSOPIDAE 1343 
for, on examination of an aphid-infested plant, these insects are usually 
first seen, the chrysopids being more difficult to find. 
The parasitic Hymenoptera and the Coccinellidae are generally 
more plentiful and more effective checks upon aphids than the chrys- 
opids, though this varies with the locality and other conditions. In 
one field where the melon aphis was plentiful, these enemies were very 
searce while Chrysopa oculata was exceedingly abundant. 
DESCRIPTIONS OF THE LIFE STAGES OF THE SPECIES 
It will be soon observed that the chief points emphasized in the 
following descriptions are color patterns. The reader is cautioned 
against too strict interpretation of color shades and of sizes and shapes 
of spots, for both are subject to variation. However, the variation does 
not extend to such lengths as to make the species difficult to recognize, 
with the possible exception of the rufilabris-plorabunda group. With a 
little practice, all the larvae described may be recognized at a glance in 
the third instar. The other instars are more difficult of recognition 
because of size and less distinct coloration. 
Chrysopa oculata Say (Plate LX XIX) 
1839 Chrysopa oculata. Say, Journ. Acad. Nat. Sci. Phila., vol. 8, p. 9-46. 
1839 Chrysopa chlorophana. Burmeister, Handbuch Ent., vol. 2, p. 979. 
1855 Chrysopa albicornis. Fitch, First report, p. 84. 
1903 Chrysopa chlorophana. Banks, Trans. Amer. Ent. Soc., vol. 29, p. 147. 
1903 Chrysopa albicornis. Banks, Trans. Amer. Ent. Soc., vol. 29, p. 149. 
1903 Chrysopa oculata. Banks, Trans. Amer. Ent. Soc., vol. 29, p. 152. 
Chrysopa albicorms Fitch is placed under C. oculata Say for the 
following reasons: 
1. There is no definite boundary between the two forms, the only 
differences being in their size and in the degree of darkening of the 
wings. A series may be readily arranged from one to the other. 
2. The great majority of specimens answering the description of 
the former are males. It has been found that the males show a tendency 
to be smaller and darker than the females. 
3. The progeny of several females answering the description of 
albicornis gave all medium-dark-winged to light-winged specimens 
(oculata). 
4. The dark specimens cross readily with any variety of C. oculata. 
5. The dark specimens occur with C. oculata in nature in the same 
habitats and have no distinguishing habits. 
6. The eges and the larvae of the two forms are indistinguishable. 
