76 MODERN CLASSIFICATION OF INSECTS. 
family Tenthredinide, I have entered into the same subject, as re- 
gards the species which have the abdomen sessile. 
The wings are four in number ; they are naked, membranous, and 
horizontal, the anterior pair being much larger than the posterior, 
with a scaly plate (tegula Laér.) at the base of the former ; they are 
moreover furnished with corneous nerves, or, more properly speaking, 
veins arranged longitudinally and transversely, but much fewer in 
number than in the Neuroptera, so that they do not forma close net- 
work, as in the latter order; the spaces, or areas, enclosed between 
these nerves are of various sizes, and are termed cells, and which are 
of great service in the investigation of the inferior groups and genera, 
as first pointed out by Moses Harris, in his Exposition of English 
Insects, published in 1782, and subsequently more fully developed by 
Jurine, in his Nouvelle Méthode de classer les Hyménopteres, Sc. (4to. 
1807).* The anterior wings are also furnished with an incrassated 
spot, termed the stigma, near the extremity of the anterior margin, 
from which proceeds a nerve of a curved form, running towards the 
tip of the wing, and enclosing one or two cells, termed marginal or 
radial; below, and running nearly parallel with this curved nerve, is 
another, connected therewith by transverse nerves, enclosing several 
cells, termed the submarginal or cubital. ‘The number of these nerves 
is, however, liable to considerable reduction, the wings being almost, 
and even entirely, destitute of nerves in some of the minute species, 
constituting the families Chalcididee and Proctotrupide. 
Another character of the order consists in the connexion, during 
flight, of the two wings on each side of the body, by means of a series 
of minute hooks along the anterior margin of posterior wings, which 
* More recently, Jurine, in the 24tn volume of the Memoirs of the Academy 
of Turin, Saint Fargeau (Hist. Nat. Hyménopt., p. 46—69.), Shuckard, in a 
memoir published in the first volume of the Transactions of the Entomol. Soc. of 
London, and in his work on the: British Fossorial Hymenoptera, Gravenhorst ( Jchneu- 
monologia Europea, vol. vi. plate 1.), Haliday (Entomol. Mag., vol. v. p. 211.), 
Professor Wesmael (Monogr. Braconides de Belgique, pl. 1.), and Dr. Th. Hartig 
(Die Aderfl. Deutehsl., pl. 7. fig. 1.) have respectively examined in great detail the 
composition of the wings of the Hymenoptera, applying distinct names to the dif- 
ferent cells and to each vein. But as the nature of the wing-ribs is now clearly 
ascertained to be that of veins, it appears to me that a more natural mode of treat- 
ing them than has hitherto been proposed must be based upon the relation of the 
different minor veins with those which are employed in the greater ascending and 
descending currents. 
