1296 Roger C. SmMitH 
tively in the field as eggs of this species, but single eggs are not unusual. 
Most of the eggs of C. quadripunctata, C. rufilabris, C. chi, and others 
of the more uncommon species, are laid singly. C. oculata and its 
varieties lay their eggs either singly or in irregular groups. 
Eggs from fertilized females in rearings nearly always hatch, the 
hatching percentage approaching 100 if conditions are not decidedly un- 
favorable. In early spring and late fall rearings, the hatching percent- 
age is lower. In one case in which 95 eggs were laid in the laboratory 
in February, 1916, by C. oculata, only 37 or 39 per cent hatched. This 
is an extremely low percentage, and was undoubtedly due to unfavor- 
able temperature during the cold nights of February and March. How- 
ever, examination of the unhatched eggs showed that the embryos of 
some were partly developed. No eggs from unfertilized females have 
hatched. They shrivel early, but retain their bluish green color. 
In two experiments, eggs of C. oculata that were completely sub- 
merged up to nineteen hours, hatched, but eggs submerged in water for 
from twenty-four to forty-eight hours all failed to hatch. It is very 
probable that eggs 
can withstand con- 
siderable rainy 
weather and sub- 
mergence for a 
short time as a re- 
SUL i Ohi vorora ss 
without injury. 
Development of 
the embryo 
The development 
of the embryo 
can be observed 
readily in Chrys- 
opa eggs. The 
embryology has 
A, Lateral view of egg of Chrysopa oculata after thirty eeoo cane Selioe oy 
ground ou ib dorsurh iA The Gany etme er eteSa Se eeeeae eed 
hours development, owing aerite’ df'alasmes SA" among them Pack. 
turning. C, Egg of C. nigricornis showing abdomen pushing : 
forward toward the venter, thus completing the turning ard ( deni ca ne 
Fic. 154. EGGS AT VARIOUS STAGES 
