156 Dr, Toke Chgpman on Latiorina orbitulus. 
its abolition in the fact that most educators of Lycaenid 
larva have observed that in the absence of attendant ants 
the gland secretion is apt to exude and accumulate over 
the gland, where it decays and moulds, and infecting the 
larva commonly leads to its death. There is also the 
pressure of the common inheritance of the abdominal 
segments which perhaps deserves a word of explanation. 
It will probably require more than this note to make 
zoologists accept it as an existing agency, but I have 
myself no doubt that it is a vera causa in cases like that 
before us. 
There is abundant ground for assuming, without going 
outside the Lepidoptera, still less citing orders of Annulosa, 
more distantly allied, in which the numbers themselves of 
the segments vary from group to group, that the abdominal 
segments have to a great extent a common inheritance, 
and vary together (from species to species). It is probable 
in a high degree that this inheritance, which tends to pass 
from one segment to another any feature such as the 
dermal armament of the dorsal region which we are con- 
sidering is in continual action, tending to eliminate the 
honey-gland and replace it by an armament similar to that 
on the other segments, and that the honey-gland is only 
preserved, where it is preserved, by its usefulness, giving it 
an efficient selective value. 
A long essay would be necessary to show how this 
common inheritance, say, of the dorsal dermal armature 
of the abdominal segments, may be found enforcing the 
uniformity of these structures. Where they differ from 
each other there is usually some very special object in 
view, but in the mass of Lepidoptera these segments are 
identically armed and coloured, yet considering how 
various this armature and colouring is in different groups, 
it might be expected that a good deal of variety would be 
found in the different segments of one larva, much more 
frequently than actually occurs, were there not some force 
keeping them together. The identical brushes on the 
first four segments in Orgyia, the black dorsal pencils in 
Acronycta leporina, which vary so much in their number 
and size, may be cited as instances where these segments 
inheriting one from another is a much more probable 
explanation than the only obvious alternative one, viz. a 
common response to a common environment. 
