126 — Transactions.—Z oology. 
Lecanio-diaspide of Targioni, Planchonia loses its antenna, Lecaniodiaspis 
keeps them. But it appears to me that there is an organic difference 
between the secretion of a test, whether of wax, or felt, or cotton, and the 
absence of any test at all. The difference between the naked genus Lecanium 
and the covered genus Ceroplastes is, I take it, much greater than that 
between Ceroplastes and Vinsonia. 
In my paper of 1878 (Trans., vol. xi., p. 207), I introduced the subsec- 
tion Lecanio-diaspide with an extension of its limits; and I was led to this 
in great measure because the term itself seemed so apt for expressing the 
main difference between certain genera and the rest of the Coccid family, 
that is, the possession of certain characters common to all Lecanide 
together with the formation of tests as in the Diaspide (though not neces- 
sarily including any pellicles). I then added to the subsection the genera 
Ctenochiton and Inglisia, and in my paper of 1881 (Trans., vol. xiv., p. 221) 
the genus Lecanochiton. 
There appears to be only one character common to all the Lecanide 
which can be easily and clearly made out. It is the presence, at the 
abdominal extremity of the female, of a more or less deep cleft, above which, 
on the dorsal side, are two small protruding (usually more or less triangular) 
lobes. Other characters, of course, exist, such as the generally monomerous 
mentum, the usually stationary position of the adult female, the antenne 
with almost always (in the adult) six or seven joints, and so on. But these 
distinctions cannot always be exactly observed. For instance, it is often 
exceedingly difficult, if not impossible, to tell whether the mentum is 
monomerous or dimerous. But, as far as my own observation goes, and 
from the description of M. Signoret and others, I know of no species of 
Lecanide which does not exhibit quite clearly enough the abdominal cleft 
‘and its two lobes. In the group Diaspide the abdomen has no such . 
appearance: there is sometimes, as in Chionaspis dubia, mihi, or Diaspis 
rose, Sandberg, a slight median depression, but the whole form of the part 
is quite distinct. In the group Coccide the abdomen either has no appear- 
ance of division, as in the Dactylopii (see fig. 19g., Trans., vol. xi., pl. 
viii.), or else ends with prominent processes, which I have called “anal 
tubercles,” as in Eriococcus hoherie, mihi (Trans., vol. xii., pl. vii., figs. 
14, 20). I append to this paper (figs. 22, 23, 24, and 25), diagrams to give 
a comparative view of the three groups. 
It follows then that the group to which an insect belongs can be at once 
discerned by reference to the abdominal extremity. There is one exception 
to this in the insect producing stick-lac, Carteria lacea, where the cleft and | 
lobes are not casily made out; and there are the genera Kermes, Pollinia, 
etc., where the adult insect shows the cleft and lobes of Lecanide while the 
young has the anal tubercles of Coccide. But exceptions prove the rule. 
