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[Vol. 87 
the first type and ten out of 16 of the second type were adopted. 
Differences between the number of emerged individuals and trans¬ 
planted immature offspring were positive in two out of 12 nests of the 
first type and six out of 16 nests of the second type. However, the 
production of the artificial colonies—although lower—was occa¬ 
sionally comparable to that of natural ones [see Pardi (1951, p. 381) 
on 6 natural nests of P. gallicus ]. 
The growth curve of three larvae in a gelatin capsule nest attended 
by six wasps and kept at about 25° C, is shown in Fig. 6. Larval 
weight, registered daily by weighing the entire cell, varied initially due 
to the different quantity of honey accumulated in the cells, then 
followed almost identical curves during the period of greatest growth 
between the 11th and 19th day. A rapid decline in weight occurred 
immediately after pupation due in part to the emission of meconium 
and, perhaps, to water loss. 
E) Orientation of pupating larvae in transparent cells 
In natural nests each pupating larva first spins a silk dome over the 
open end of its cell, then turns back and spins the posterior end of the 
cocoon, returning finally to its original position. Some of the larvae 
raised in transparent cells failed to turn after spinning the posterior 
end of their cocoons and pupated without reorienting to the front of 
the cells. The effect of light on this orientation was tested by rearing 
larvae in three types of cell: transparent capsules illuminated from the 
side, capsules with opaque walls and transparent bottoms illum¬ 
inated from behind, and completely opaque capsules illuminated 
from the front. The results obtained with these nests, shown in Table 
II suggest the presence of a phototactic component in the orientation 
of the larva during pupal formation. Further tests are in progress to 
test for the presence of other components as well. 
F) Malformation of specimens emerged from artificial nests 
The shape and position of the wings in some newly emerged 
imagoes raised in gelatine capsules were so malformed as to prohibit 
flight. When raised in shorter-than-normal cells, the body was 
compressed cephalo-caudally (Fig. 7). Specimens reared in plastic 
straws cells seldom presented such anomalies. 
