251 
from 14 to 2 inches in length, and is nearly white in color. The head 
and mouth parts (Fig. 36 e, f, g) are remarkably well developed for a 
Hymenopterous larva. The cocoon is constructed very rapidly, not 
Fic. 36.—Sphecius speciosus: a, larva; b, pupatrom below; c, same, from side—natural size; e, head of 
larva; f, labium of same; g, maxilla of same—enlarged (original). 
more than two days being required for this purpose. The larva in the 
act of constructing its cocoon is shown-in Fig. 37. The cocoon at 
first consists of an open cylinder, the ends of which-are ultimately 
closed. It is constructed of earth, with enough silk incorporated to 
makearatherdense — 
body. About the 
middle of the cocoon 
are a number (about 
a dozen) of very 
curious pores (Fig. 
38) and these have, 
so far as I know, 
never before been 
observed or de- 
scribed in the co- 
coons of any other 
fossorial wasps, and 
their use can. only 
be surmised. 
In the completed 
cocoon they are cap- 
ped on the inside, but iene construction they must have been open 
and afforded a means of entrance for air, for ventilation, and respira- 
tion. They are placed in two irregular rows on one side of the cocoon 
and rise like minute tubercles with a truncate rim somewhat above the 
general surface exteriorly. They are composed of a glue-like substance 
and penetrate the wall of the cocoon, broadening to the inside, where 
Fie. 37.—Larva of Sphecius spinning its cocoon—natural size (original). 
