Page 1 : Insect wings, Insects are the only invertebrates possessing wings and capable of true flight, Based on the presence or absence of wings, class insecta is divided into two subclasses. 1. Apterygota 2. Pterygota., The primitive apterygotes are wingless. Eg: Silver fish and Spring tails, , Based on the degree of development of wings the insects may be classified into three forms , Macropterous, , Brachypterous , and Apterous.

Page 5 : Wings are very thin broad leaf like structures strengthened by a number of hollow narrow tubular structures called veins. Arrangement of veins on wing surface is, known as Wing venation, which consists of two types of veins, 1. Longitudinal veins : Extend from base of the wing to the margin. They maybe convex (∩) or concave (U), 2. Cross veins : That interlink the longitudinal veins, , The insect wings may some times possess some pigmented spot near coastal margin known as pterostigma or stigma as in Odonata (dragon flies and damsel flies)

Page 6 : 1. Costa (C) : It forms the thickened anterior margin of the wing (costal) and is un-branched. and is convex, 2. Sub costa (Sc) : It runs immediately below the costa always in the bottom of a trough between C and R . It is forked distally .The two branches of SC are Sc1 and Sc2 and is concave, 3. Radial vein (R ): It is the next main vein , stout and connects at the base with second auxillary sclerite , it divided in to two branches R1 and Rs (Radial sector). R1 goes directly towards apical margin and is convex; Rs is concave and divided in to 4 branches, R2, R3,R4, R5., 4. Media (M) It is one of the two veins articulating with some of the small median seclerites. It is divided in two branches 1. Media anterior (MA) which is convex and , 2.Media posterior(MP) and is concave. Media anterior is again divided into MA1 and MA2. Median posterior is again divided, in to MP1, MP2, MP3, MP4.

Page 7 : 5. Cubitus (Cu): It articulates with median auxillary sclerite. Cubitus is divided into convex CU1 and concave CU2. CU1 is again divided into CU1a and CU1b., 6. Anal veins (A) : These veins are convex. They are individual un-branched, 1-3 in number., 1 or 2 jugal veins (unbranched) are present in the jugal lobe of the forewing, , Cross veins, Humeral cross vein (h) : between costa and subcosta, Radial cross vein (r ) : between radius and radial sector, Sectorial cross veins (s): between sub branches of radial sector, Radio medial cross vein (r-m): between radius and media, Medical cross veins : between branches of media, Medio-cubital veins : between media and cubit