362 Dr. F. Meinert on the Campodew, 
sects, it has been attempted by several authors to maintain the 
subdivision of the whole class (first indicated by him) into 
Mandibulata (Masticatores) and Haustellata (Suctores),—the 
former division comprising Eleutherata, Ulonata (Synistata), and 
Piezata, the latter Glossata, Antliata, and Rhynchota. It may 
be objected with truth against this classification that many 
so-called Mandibulata or Masticatores have but imperfectly deve- 
loped mandibles, unfit for mastication, whilst many Haustellata 
are without any vestige of an haustellum or sucking-tube. But 
its principal defect seems to be that it disregards natural rela- 
tionships in separating two orders. so nearly allied as Piezata 
and Glossata, and associating the latter with animals with whom 
they do not agree as regards the structure of the mouth, except 
masmuch as the organs of the mouth are generally prolonged— 
a circumstance which has no typical but merely a biological sig- 
nificance. It is not, however, my intention by these remarks to 
derogate from the importance of the organs of the mouth for 
the establishment of principal as well as of subordinate divisions 
of insects, so clearly demonstrated by the imperishable works of 
the great Danish entomologist; nor do I deny that two principal 
types are observable in the structure of the mouth in that class. 
But I believe that their essential point of difference has been 
overlooked, and therefore an erroneous classification adopted. 
This essential point of difference is, in my opinion, to be found 
in the position of the first two pairs of appendages of the mouth 
with reference to the skull *. 
One of these two principal types is characterized by the man- 
dibles articulating with the skull by means of a hinge-joint, while 
the maxille are connected with the skull through a less perfect 
articulation, sometimes merely sliding on its anterior margin, 
which surrounds the mouth. This arrangement leaves the or- 
gans of the mouth entirely free outside the mouth ; they can be 
moved laterally, and are so far fit for biting; and whilst the 
mandibles are altogether incapable of being protruded in front 
of the mouth, the maxille are only in a very limited degree 
capable of such a displacement}. The appendages of the mouth 
cannot, therefore, be used as stinging-instruments ; and when 
* The first indication of this view may be found in a passage of the 
important paper by Latreille, ‘De quelques Appendices particuliers du 
Thorax de divers Insectes”’ (Mém.du Muséum, 1821,t. vii. p.20, concluding 
note, “ La nature me parait avoir formé,” etc.). But he has not carried it 
out in practice; otherwise he could not have placed Glossata amongst 
Suctores. 
t The apparent protrusion of the proboscis in bees, which is formed by 
the second and third pair of appendages of the mouth, consists principally . 
in its being stretched out, whilst ordinarily it is folded up ; but it is always 
outside the mouth. 
