PHYSIOLOGICAL ANIMAL GEOGRAPHY 581 
c. Factors controlling egg-laying. The relations to light and 
leaves are interesting. The larvae were frequently at the edges 
of the piles of leaves in such positions as eggs might be placed 
by females, the posterior half of whose bodies were concealed by 
the leaves (fig. 18). Females have been found making ovipositor 
holes, when the posterior two-thirds of the body was under a 
leaf. 
The depositing of eggs in the unshaded portions of the cages 
may be due to the reduced intensity of light, or the shadow of 
the cage frames, which falls upon some parts of the soil at any 
Fig. 18 Showing the position of the larvae of C. sexguttata in a cage. The 
black spots represent the larval holes. The stippled portion represents the 
approximate area in shadow during the middle of the day. 
given time. Nearly all parts pass into shadow for a time during 
each day. All of the eggs may then have been deposited when 
all or a part of the animal’s body wasin the shade. The reduction 
of the intensity of the light to one third that of normal out-of- 
door light may act as a partial shadow to this species. The 
experiments will be repeated in the full sunlight. 
As will be seen by an inspection of the tables most of the eggs 
were deposited in the sand with a little humus. None were laid 
in pure forest humus. The fresh sand and clay were ignored when 
they were allowed to remain dry. Muddy places were avoided. 
It is evident that egg-laying is governed by (a) kind of soil, (6) 
soil moisture, (c) slope, (d) light, (e) temperature (activity only 
