BMBIA MAJOR FROM THE HIMALAYAS. 171 



clothed with stiff black hairs. The mesothorax is the largest division of the three, sub- 

 quadrate in shape, slightly broader than long, and wider than the prothorax. Its anterior 

 margin is clothed with pilose hairs. The metathorax is entirely glabrous and a little 

 shorter than the mesothorax. The fore-wings vary in length from 8 5-1T25 mm., and 

 their breadth varies from 275-3 - 5 mm. The hind-wings vary from 8-10*5 mm. in 

 length and 25-35 mm. in breadth. The length of the wings compared with that of 

 the abdomen exhibits a certain amount of variation in different individuals. In some 

 examples the apices of the closed wings extend a little beyond the tips of tbe cerci, 

 while in other specimens they only reach far enough posteriorly to cover a portion of 

 the basal joint alone of each cercus. The neuration exhibits a very wide range of 

 individual variation, especially as regards the transverse veins, and, furthermore, the 

 veins of the right and left wings frequently differ from one another. If examined 

 immediately after the last ecdysis, the wings are seen to be hyaline and the veins are 

 more clearly exhibited. WTien the full darkening of the chitin is attained the veins 

 are reduced to the condition of being merely darker lines of thickened cuticle following 

 the original neuration. A comparison of the wings in the hyaline and fully developed 

 conditions, shows that the neuration undergoes practically no reduction or modification 

 during the period taken by the wing-membranes to harden and mature. In some 

 specimens, however, certain of the longitudinal veins exhibit a tendency to dwindle away 

 at their apices, before quite reaching the margin of the wing. In this respect Embia major 

 is an example of the first step in the reduction of the wing neuration, which attains its 

 maximum in the genus Oligotoma. The surface of the wings is clothed with minute pilose 

 hairs together w T ith longitudinal rows of longer hairs. These latter are disposed along 

 the courses of the veins and in the areas between the veins (text-fig. 1), but are entirely 

 wanting from the hyaline longitudinal areas of the wing-membrane. The margins of the 

 wings are fringed with regularly arranged longish setae. In the text-figure the neuration 

 of an average specimen is represented. The terminology followed is that advocated 

 by Comstock and Needham (1898, p. 423), which is based on a study of the phylogenetic 

 development of the wing-veins of Insects. The costal vein (c.) is confluent with the 

 anterior margin in both pairs of wings. The subcostal vein (sc.) is short, being less than 

 one-third of the length of the wing ; it tapers to a point and dwindles away altogether. 

 This vein is thickly chitinised, and just visible to the unaided eye. The radial vein (r.) 

 is the most conspicuous vein of all, being very strongly chitinised and much thickened 

 in calibre. Running parallel to, and almost in contact with the anterior and posterior 

 margins of the radial vein, are a pair of very fine dull red lines (al. and pi. in text-fig. 1). 

 These two lines terminate a short distance before reaching the junction of the radial and 

 median veins. They are termed by Enderlein (1912, p. 10) the " Radiussaumlinien " 

 (Radiolimbolarien), and by Krauss (1911, p. 7) the (i Radius- Nebenlinien." They possess 

 a certain amount of value as a specific character, and may be conveniently referred to 

 as the anterior and posterior radial lines. A short distance before reaching the apex of 

 the wing the radial vein joins the median. A variable series of 4-7 transverse veins, 

 situated in the distal half of each wing, unite the costal with the radial vein. The median 

 vein and its branches are distributed over about one-half the total area of each win"- 



