The wing neuration is always rather troublesome, as various authors use different names for the veins and cells. To begin with the anterior wing (e), there are four nerves which start from the base and run horizontally; the first of these, which forms the anterior margin of the wing, is called the costal nervure (1); immediately below this, and running almost parallel to it with scarcely any space between them, is the post-costal nervure (2); these end in the stigma (s), a dark in-crassation towards the apex of the wing; from the stigma a nerve, curving first downwards and then up to the anterior margin of the wing, encloses the marginal cell (A). Below the post-costal nervure, and situated about the centre of the wing, is the third longitudinal nervure called the median nervure (3); behind this again runs the posterior nervure (4), and behind that the actual margin of the wing which is not provided with a protecting nervure, but is only folded back so as to receive the hooks of the posterior wing. Across the wing at, roughly, about a third of its length from the body runs the basal nervure (5); this extends in a somewhat zigzag line from the post-costal to the posterior nervure crossing the median, and
thereby enclosing two cells, the upper basal cell (B) and the lower basal cell (C). From the centre of the apical nerve of each of these cells extends a longitudinal nervure; the upper of these runs out nearly to the apical margin of the wing and is called the cubital nervure (6); this is united to the nervure of the marginal cell by one, two, or three cross nervures, enclosing thereby one, two, or three cells called the first (D), second (E), and third (F) submarginal cells. The nervure from the lower basal cell is a short one, as it is met by a cross nervure called the first recurrent nervure (10), which runs from the cubital to the posterior, thereby enclosing two cells, the first (G) and second (H) discoidal. The second recurrent (11) leaves the cubital nearer the apex of the wing than the first, meeting a nervure which, springing from the outer posterior angle of the second discoidal, closes the third discoidal (I), and, curving slightly upwards, nearly reaches the apical margin of the wing. Beyond the second recurrent, and behind this last nervure which we have been talking about, are two spaces not actually enclosed, but called the first (J) and second (K) apical cells.
The posterior wings have very few cells.
Like the anterior pair they have three longitudinal nervures; the anterior (7), which runs close and parallel to the anterior nerveless margin, and often touches it at about half the length of the wing; the median (8) and posterior (9) run in diverging lines from the base towards the exterior margin of the wing, the anterior and median nervures being almost always joined by a cross nervure, and the median usually united to the posterior by a cross or curved nervure. The actual base of the anterior wing is covered by a little convex somewhat shell-like cap, called the tegula (T). The abdomen is composed of a series of segments in linear arrangement (c1 c2, etc.). These call for no special remark, beyond what has been said in the chapter on males and females, but those who wish to investigate the very interesting questions connected with the terminal segments of these creatures should consult some more technical work.[[3]] The arrangements of the mouth parts and of the apical segments of the Hymenoptera afford perhaps the most important structural
characters of the order, but they involve an amount of dissection and study which can only be undertaken by those who are inclined to give themselves up to this subject as a speciality.
INDEX
Abdomen, [125]
Acetabulum, [135]