115 
sept. is 97 .] Packard : Transformations of Hymenoptera. 
Of the first brood of males and females the latter were not nearly so 
dark and hairy as the males, which were just ready to leave their cells 
except one which was a subimago. 
. 1 first observed this dimorphism in the pupae taken from this nest • 
it was better seen than in examining the adult bees. 
The eggs are elongated cylindrical, with the ends truncated and 
rounded off; and they are slightly curved in themselves. 
Larva of Worker.— In their general form the larvae of Bombus agree 
closely with those of Apis and Megachile. In outline lunoid the body 
is thick, cylindrical, though a little flattened, and the rings rapidly 
diminish in width towards each end of the body. In their natural atti¬ 
tude the larvae when in their cells are doubled upon themselves, so that 
the under side of the head is closely oppressed to the tip of the abdo¬ 
men. The enlarged pleural surface, which forms a raised lateral rid-e, 
aids in giving, the flattened appearance to the body. On the hinder 
half of each ring of the body is a tergal raised, flattened band proceed¬ 
ing on each side from the lateral ridge, leaving a transverse depressed 
ovate lanceolate area, at each end of which is a spiracle. There are ten 
spiracles, one for each thoracic ring and one on each of the first seven 
abdominal rings. 
Beneath the body is flattened, and the sternal region is very distinct 
from the raised pleura. Each ring has its surface raised into two trails- 
verse ridges. 
Above, the thoracic rings differ from the abdominal ones in having 
the raised portions cover nearly the whole surface, which actually takes 
place in the prothoracic ring. It is on this raised portion that the 
minute horny acute papillae are situated; two for each second and third 
ring, and three on the middle of the prothoracic ring in a transverse 
line. . The arrangement of these tubercles does not essentially vary in 
the different species. The prothoracic ring is a third narrower than in 
the metathoracic ring, though as long. The tenth and abdominal ring 
is in outline equal in size to that of the head, being orbicular when seen 
from behind. Its surface is marked below by an oblong square raised 
mesial portion, twice as long as broad. There is no anal outlet since the 
intestine is a blind sac. The p and $ genitals can be distinctly seen, 
so that the sexes of the larvse can be easily distinguished. 
Of the two pairs of stylets on the ninth ring, the most basal and outer 
are triangular, and the inner sides nearly meet over the mesial line of 
the body. The smaller outer and more remote pair have their greatest 
length across the ring; their tips nearly meet on the mesial line of the 
