152 
Psyche 
[June-August 
Table 1. 
Sex of Imagines and Pupae produced by Paedogenetic Larvae of Known 
Paedogenetic Origin. 
Culture 
Pupae No. of 9 9 No. oid' d' Total Per Cent 
arose by oid d 
Bj2, Ci2 
M79 
MNO 340 
4XXF3 
4XXF6 (M222) 
4 XXF 5 (M223) 
4 XXF 5 (M224) 
X8F2 
MN320 
CO23 
A. 
crowding 10 18 
crowding 1 1 
crowding 1 1 
B. Female-producing strain, 
crowding 38 0 
crowding 26 0 
crowding 23 0 
crowding 59 0 
crowding 1 0 
C. Male-producing strains, 
crowding 0 5 
CO 2 0 5 
28 
64.3 
2 
50.0 
2 
50.0 
38 
0.0 
26 
0.0 
23 
0.0 
59 
0.0 
1 
0.0 
5 
100.0 
5 
100.0 
All cultures were maintained on the standard artificial 
culture medium, described earlier in this paper, under as nearly 
identical external conditions as possible, save culture CO 2 3. 
The mother of the five imagines which appeared in this culture 
was treated with carbon dixoide at birth, and for some time 
subsequently, after which she was transferred to the standard 
medium employed in these studies. In all cases cultures were 
maintained in closed boxes in the same incubator, thus being 
exposed to similar conditions in respect to temperature, humidity, 
and light, as well as food. Thus the conclusion seems warranted 
that the observed sex-ratios are the expression of an internal 
mechanism, which, in the present instance in all probability, 
has not been greatly affected by external conditions (save 
possibly in the case of the strain produced by the paedogenetic 
mother larva which was treated with carbon dioxide.) Sufficient 
data are not yet at hand to warrant a statement concerning 
whether or not the carbon dioxide treatment changes the sex- 
ratio as in Cladocera (Banta 1923). 
Summary. 
Males as well as females arise from mass cultures of larvse 
that have been produced by paedogenesis in Oligarces sp. 
But males and females are not produced by the same in- 
dividual, under normal conditions. 
