Lameere's classification is founded on the number of abdominal sterna, the nervuration of the wings, the number of malpighian tubules (whether four or six) and other structural characters.
- In this tribe may be included a number of families distinguished by the softness of the cuticle, the presence of seven or eight abdominal sterna and of four malpighian tubes, and the firm, well-arm oured larva (fig.
They may be distinguished from the Malacodermata by the presence of only five or six abdominal sterna, while six malpighian tubes are present in some of the families.
- This is an important tribe of beetles, including families with four malpighian tubes and only five or six abdominal sterna, while in the thorax there is a backwardly directed process of the prosternum that fits into a mesosternal cavity.
Ileymons, the hypopharynx represents the sterna of all the jaw-bearing somites, but other students consider that it belongs to the mandibular and first maxillary segments, or entirely to the segment of the first maxillae.
In the abdominal exoskeleton the segmental structure is very clearly marked, a series of sclerites - dorsal terga and abdominal sterna - being connected by pale, feebly chitinized cuticle, so that considerable freedom of movement between the segments is possible.
The first and second abdominal sterna are often suppressed or reduced, on account of the strong development of the hind-legs.
- Procellaria, Diomedea, Larus, Sterna, Rhynchops.
No distinct respiratory stigmata behind the sterna of the 1st and 2nd somites of the opisthosoma.
- Opisthosoma without trace of separate terga and sterna, the segmentation merely represented posteriorly by slight integumental folds and the sterna of the 1st and 2nd somites by the opercular plates of the pulmonary sacs.
Genera: (a) Anas, Mergus, Phaethon, Plotus; (b) Rhyncops, Diomedea, Alca, Procellaria, Pelecanus, Larus, Sterna, Colymbus.
The more common sea-birds are the Sula variegate or guano-bird, a large gull called the Larus modestus, the Pelecanus thayus, and the Sterna Ynca, a beautiful tern with curved white feathers on each side of the head.
This last is the beautiful roseate tern, Sterna dougalli; the other is the black tern, Hydrochelidon nigra, belonging to a genus in which the toes are only halfwebbed, of small size and dark leaden-grey plumage.
It is without doubt the Sterna of Turner, and in former days was abundant in many parts of the fen country,' to say nothing of other districts.
All the species already mentioned, except the black tern, have much the same general coloration species as " nostrati lingua sterna appellata."
To Turner's name, repeated by Gesner and other authors, we owe the introduction by Linnaeus of Sterna into scientific nomenclature.
2 Linnaeus's diagnosis of his Sterna hirundo points to his having had an " arctic " tern before him; but it is certain that he did not suspect that specific appellation (already used by other writers for the " common " tern) to cover a second species.
13, sterna of the thoracic somites, from within.