Maskell. — On Coccididas. 87 



points. But, with regard to the anal tubercles, the remarks of 

 Mr. Newstead {loc. cit.) lead me to treat these organs with 

 some detail. 



After stating that in D. nipcB the tubercles are "very 

 large," he says, "in the form of the antennal joints it is 

 clearly Dactylopid, but the very conspicuous anal lobes are 

 abnormal." I do not think so, for reasons to be mentioned 

 presently. 



In absolute strictness, I suppose that we ought not to look 

 upon the tubercles of, say, Eriococciis and Dactylopius as 

 morphologically distinct at all. In both cases they seem to 

 be only processes visible on each side of the abdominal ex- 

 tremity, near to the anal ring; and they always bear a more 

 or less numerous arrangement of hairs or spines. Carrying 

 this view a little further, we might say that they correspond 

 sufficiently with the abdominal lobes of the Lecanids. But, 

 when v;e come to attempt a clear and convenient classifica- 

 tion, we find that the forms possessing antennae with short 

 terminal joints and anal rings with eight hairs exhibit almost 

 always tubercles differing considerably from those of the forms 

 with long terminal joints and anal rings with six hairs. 

 Absolute and severe uniformity is not to be expected when we 

 are dealing with Coccids ; yet the rule is as just stated. After 

 nearly twenty years of experience, during which I have 

 examined many hundreds of specimens of both kinds, I cannot 

 say that there is any real difficulty in separating them. Some 

 of the AcanthococcincB — e.g., Bliizococcus cas7iarin<^, Mask., or 

 Eriococciis turgijjcs, Mask. — have comparatively small tu- 

 bercles: some Dactylopids — e.g., Dactylopius nvpcd, Mask., or 

 Bipersia fagi, Mask. — have comparatively large ones : but 

 there is no mistaking their character. Bipersia fagi, Mask., 

 is one of the Dactylopids I know of with perhaj)s the largest 

 tubercles : Bliizococcus grandis. Mask., has perhaps the 

 smallest tubercles of the Acanthococcids. Yet there is a very 

 long way between the two. 



The form of the tubercles in a Dactylopid is usually 

 rounder and less cylindrical than in an Acanthococcid ; their 

 spines and setae, where present, are more scattered ; and the 

 margins are less irregular. As a rule, also, they appear to be 

 less chitinous. After treatment with potash (as described in 

 my paper of 1891, p. 3), it will usually be found that the feet, 

 antennae, and rostrum of a specimen remain of a much darker 

 colour, with more solid appearance, than the rest of the body ; 

 so also do the abdominal lobes of a Lecanid and the anal 

 tubercles of an Acanthococcid ; but the tubercles of a Dacty- 

 lopid seem generally to be less hard. There are exceptions, 

 as in Bipersia fagi, where the tubercles remain slightly 

 darker than the body, but these are few. Even in Eriococcus 



