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10 I1.—CHARACTERS AND STRUCTURE OF THE LEPIDOPTERA. 
serves, in conjunction with the frenulum, to lock the wings 
together during flight. In the female both these organs 
are often very imperfectly developed, the frenulum con- 
sisting of several bristly hairs, and the retinaculum of a 
group of stiff scales. In many of the Lepidoptera both 
frenulum and retinaculum are entirely wanting; in the 
Hepialidae and Micropterygidae a membranous or spine- 
like process called the jugum rises from the the dorsum of 
the fore-wing near the base (see Plate B., figs. 22 and 28, 
and Plate A., figs. 10, 14). 
‘““The wings are traversed by a system of Veins— 
tubular structures which serve at once as extensions of the 
tracheal system, and to form a stiff framework for the sup- 
port of the wing. In the normal type of Lepidoptera the 
fore-wings possess three free veins towards the dorsum, 
termed la, 1b, and 1c; a central cell, out of which rise ten 
veins, numbered 2 to 11, the sides of the cell being known 
as the upper median, lower median, and transverse veins 
respectively ; and a free subcostal vein, numbered 12; whilst 
the hind-wings differ from the fore-wings in having only 
six veins rising from the central cell, numbered 2 to 7, so 
that the free subcostal vein is numbered 8 (sce Plate B., 
figs. 83 and 4, assumed type of neuration of a Lepidopterous 
insect). In some forms a forked parting-vein traverses the 
middle of the cell longitudinally, and a second parting-vein 
traverses the upper portion, so as to form a secondary cell; 
but these are more frequently absent or represented only 
by folds in the membrane. In a few forms there is a ten- 
dency to the production of several false veins, termed 
pseudoneuria, appearing as short branches from the sub- 
costal vein of the hind-wings to the costa; these are thicken- 
ings of the membrane, and are commonly very irregular 
and variable, often uneven in thickness or incomplete. 
Sometimes one of these near the base is better de- 
veloped and more permanent in character; it is then termed 
the precostal spur (see Plate B., figs., 8° and 27°). Modi- 
fications in the general arrangement of the veins may arise 
through any of the following processes, viz.: (1) obso- 
lescence, when a vein loses its normal tubular structure, 
becoming attenuated and reduced in substance, until it 
appears a mere fold of the membrane (Plate C., fig. 57, 
vein 5 in hind-wings of Declana) ; (2) stalking, when the 
two veins are fused together for a portion of their length 
from their base, so as to appear to rise on a common stalk 
(Plate C., fig. 34, veins 6 and 7 in hind-wing of Hydrio- 
mena); (3) coincidence, when two veins are fused together 
for the whole of their length, so that one appears entirely 
absent, an extreme form of stalking; (4) anastomosis, when 
two veins rise separate, meet, and are fused together for a 
certain distance, and then separate again (Plate C., fig. 23, 
veins 7 and 8 in the hind-wings of the @ of Z'atosoma) ; 
(5) concurrence, when a vein rises separate, runs into 
another, and does not separate again, an extreme form of 
anastomosis; (6) connection, when two veins are connected 
by a short transverse bar passing from one to the other, a 
special form of anastomosis, evolved from the ordinary 
form under the influence of a tendency to lateral extension 
Plate C., fig. 28, veins 7 and 8 in hind-wing of Paradetis). 
Vein 1b in both wings is often fureate at the base. 
‘« The type of veins in the Hepialdae and Microptery- 
gidae differs from that described above in two essential 
particulars, viz.: (1) there may be three additional veins in 
the fore-wings, rising out of vein 11 or 12; and (2) the 
veins of the hind-wings are practically identical in number 
and structure with those of the fore-wings, being thus much 
more numerous than in the ordinary type. There is also 
often a system of cross-bars between the veins near the base 
of the wing (Plate B., figs. 22 and 23, neuration of 
Hepialus (Plate A., figs. 14, 15, neuration of Sabatinca.)* 
‘‘The structure of the veins can be best observed on 
the under surface of the wing, where they are more pro- 
minent. The student should begin by completely denud- 
ing of seales a few wings of common species: the wing 
should be cut off and laid on a moistened piece of glass, 
to which it will adhere; the seales should then be removed, 
first from one surface and then from the other, with a fine, 
moist ecamel’s hair-brush—an operation requiring a little 
patience and delicacy of touch; the veins will thus be ren- 
dered conspicuous.t When, however, the student has 
familiarised himself with the general subject, it will 
not be found necessary in practice to resort to this process ; 
most details will be easily observed without denudation¢ ; 
where this is not the case (as where the veins are closely 

*It should be explained that the above method of describing 
the wing veins of the Lepidoptera is that which has hitherto been 
in general use by British lepidopterists, and that practically all 
the genera of New Zealand Lepidoptera, so far described, are 
characterized on this basis. Its retention in the present work 
is therefore fully justified. A uniform system of notation of the 
wing-veins supposed to be applicable to all the orders of insects 
has, however, been formulated by Comstock and Needham and a 
complete exposition of the subject may be found in a work enti- 
tled “The Wings of Insects,” published by J. H. Comstock in 
1918. This system has been adopted by a considerable number 
of entomologists, including some lepidopterists, and as time goes 
on its more general adoption appears possible. Plate B, figs. 7 
and 8, show the Comstock-Needham notation as applied to the 
wing-veins of a lepidopterous insect, and the following table 
gives a comparison of the two systems:— 
British system. Comstock and Needham. 
Costa C 
1, Subcosta Sc 
11 Radius-one R, 
10 Radius-two R? 
9 Radius-three Ry 
8 Radius-four Ry 
7 Radius-five R,; 
6 Media-one M? 
5 Media-two M? 
4 Media-three M; 
3 Cubitus-one Cut 
2 Cubitus-two Cu, 
le 1st Anal ist A 
1b 2nd Anal 2nd A 
la 3rd Anal 3rd A 
By means of this table, and the figures 7 and 8 on Plate B, the 
Comstock-Needham notation may, if desired, be applied to any 
figure of neuration given in this work. 
yFor the examination of the wings taken from dried speci- 
mens, immersion in methylated spirits renders the veins visible 
after partial denudation with the camel’s-hair brush. With recent 
specimens, however, the scales can easily be entirely removed. 
tI have found considerable difficulty and uncertainty in 
examining the neuration of undenuded specimens.- 

