90 
(Fig. 39) near its base. Two were examined—one measured 6.5 
Mitinelees long by 1.4 in diameter; the other 7. by 1.5 mm. 
They were rather dull creamy white, slightly thickened at the 
head end, as viewed from above almost straight, laterally slightly 
curved so as to conform with the curvature of the spider’s body. 
Incubation in one case was a little over three days. The wasp 
grub feeds four or five days fixed almost immovably on the 
spider’s abdomen, and during this time seems to have cast off its 
skin once. Thereafter becoming more active, it uses its jaws 
more for chewing than for pricking, and 
rapidly consumes the harder portions of 
the victim’s anatomy. It finally makes use 
of the more anterior part of the underside 
of its body as a table, eating into a dark 
Fig. 40. Mature larva of uninviting mess thereon—the remnants of 
M. violacea with rem- the spider plus debris, ete.y Finally hav- 
nant of spider on its . 5 
lap. About natural size, 4g consumed all, the grub measures, when 
straightened out, from 27 to 34 millime- 
ters, or over an inch long, with the greatest width about 9 mm. 
It is shining white, smooth and well segmented, with the lateral 
fold strong. The fat bodies are small, intersegmental and dor- 
sal. The anal segments are yellowish. The head is moderately 
large with the usual brownish oblique facial lines. About seven 
cays after hatching it is full fed (Fig. 40), and soon commences 
spinning a cocoon. ‘This is a matter of two days or more. When 
complete the cocoon 1s about 28 mm. long and 1 mm. wide, broader 
at the head end and tapering posteriorly, (Fig. 41). It is golden 
brown and rather shiny, and it lies be the longer axis of the 
cell, its darkened, more pointed tail end touching the lower or pos- 
terior end of the cell; while the body of the structure is well hung 
by supporting threads. The broader, rounded head end is very 
nearly in contact with the lower part of the cell cap. When held 
up to the light the resting larva or pupa is easily visible through 
the thin walls of the cocoon. The larva may wriggle quite audibly 
in this enclosure. 
We must bear in mind that the cell rests directly upon the tree 
hollow, which usually forms a large part of the floor over which, 
and prior to spinning its cocoon, the larva of Macromeris weaves 
a sheet of silk, thus making its cell more impervious and 
secure. In examining the cells of one of these insects it will 


y It is interesting to note that this method of feeding is not confined to solitary 
wasps. Wheeler (1900), p. 295, says regarding the ponerine ant Odontomachus 
clarus in Texas: ‘‘These larvae are placed on their broad backs and their heads 
and necks are folded over onto the concave ventral surface, which serves as a table 
or trough on which the foode is placed by the workers.’’ 
