566 VICTOR E. SHELFORD 
when not fed, devour their own species. The food relations are, 
then, highly regulatory, the animal feeding on available food. 
4. Experimental studies of habitat selection. a. Methods of 
experimentation.‘ Do the adults select their egg-laying place? 
To answer this question, adults were placed in cages containing 
soil of several kinds. Each kind was so arranged into steep and 
level parts, that about one square foot of each type was exposed. 
The adults placed in the cage were taken when the species was 
copulating freely. The soil was kept very moist up to the time 
the first ovipositor holes were made because this species lays only 
in moist soil. After this the wetting of the soil must be done very 
cautiously, so as to prevent washing eggs from the ground in steep 
parts. Accordingly, the holes were not obliterated from day 
to day and the counts are not accurate for the soil in which a 
large number were made because eggs are sometimes laid very 
close together and adjoining holes destroyed. Some eggs are 
deposited in irregular cracks and crevices where they are likely 
to be overlooked. The greatest care was taken to discover every 
hole made in the soils in which larvae do not occur in nature. 
b. Results. The following table shows the approximate 
number of holes made in the clay and probably the actual number 
TABLE 1 
The distribution of ovipositor holes and larvae of C. purpurea limbalis under experi- 
mental conditions 
SAS | CLAY, 9 PTS. POREST | HUMUS, | pT. | CLEAN 
= HUMUS, | PT. | HUMUS | SAND, 9 PTS. | SAND 
Sih al s BAI lh Aes Li: | Sula 
| ies pa ees +. | — 
OR ih eh Holes 5.5) oO) ysineed) 0 0 0/0] 0 07 Orie 
\Larvae.....: 9 0 0 OVO OnieeO 0 | 0;|0 
Pa aE Holes....... 21 Bip] 0 dO", | 0 04)= SON yenO. a Galea 
; 2 = hiayaes ae, | 12 a 0) OM nO | 0 0 0 |10;0 
Tet Ca \Holes.......| 17+ 7+ i! 0 | 0 | 0 0 0 | 0/0 
|Larvae......| 24 10 1 ON Os Os = 0 QO One 
| 
S = steep; L = level. 
* Each experiment requires daily attention for from one to two months, as well 
as considerable greenhouse space. 
