90 Mr. A.S. Packard on the Development 
pause in the metamorphosis for a special biological design, such 
as obtains in the Lepidoptera and the majority of lower Insects, 
The terms larva, pupa, and imago are therefore not absolute 
terms. 
Subimago State. 
Certain individuals which would upon a casual glance be mis- 
taken for “pup” differed so much from what we have called 
pupze above, that they may be said to be analogous to the sub- 
amago state of Ephemeride. In this state the arthroderm, 
owing to the rapid deposition of chitine, is denser and harder ; 
the wings are as large as in the perfect bee, and the joints of 
the legs are spiny, while the ovipositor has become wholly 
withdrawn within the walls of the abdomen. 
In some specimens, remains of a thin pellicle were found upon 
the extremities ; so that we are neither justified in calling this 
individual an imago nor, on the other hand, a pupa. The indivi- 
duals had not left their cells. Their feet had not yet been used 
for purposes of locomotion, nor their jaws to assist in making 
their way out of their cells, while the hairs are nearly concolo- 
rous all over the body, though very faintly shaded with yellowish 
on the dorsal and lateral portion; so that the species can be 
distinguished, as some of the specific characters depending on 
ornamentation are at this time apparent. We have observed 
facts indicating three moultings of the skin during the so-called 
pupa state, in distinction from the larval and imago states ; and it 
is highly probable that there are more. During the larval con- 
dition it would be safe to say that there are four distinct moult- 
ings, as there are five distinct sizes of larve. In some of the 
eges the larval forms can be indistinctly seen through the thin 
walls, which we would homologize with the skin of the insect 
after birth; for the fertilized egg must be regarded as the 
insect in its inception, in a state equivalent to the larval, pupal, 
or perfect state of the insect. The genus Bombus, therefore, 
may be considered to undergo a series of at least ten moultings 
of the skin; and we are inclined to think further observations 
will tend to increase the number, Lubbock * has described 
twenty in Ephemera; and five have been noticed in several 
genera, such as Meloé and others. 
The sexes of the larve can be easily distinguished, as the 
genital armature appears through the transparent skin, 
The specific differences between the larve of the different 
species of Bombus are of the slightest possible amount, as they 
only differ in size, the rings of the body being smooth or rough, 
* Trans. Linn. Soc. yol. xxiv. part 2 (1863). 
