Insect transformation / by George H. Carpenter.

  • George Herbert Carpenter
Date:
1921
Catalogue details

Licence: In copyright

Credit: Insect transformation / by George H. Carpenter. Source: Wellcome Collection.

    33/320 (page 17)
    gives off the branched radial sector. Close alongside the radial is the mediariy though this springs in some cases from the hinder group of sclerites, associated in its origin with the cuhital and anal nervures, the last-named two or three in number. The area traversed by these anal nervures in the hindwing is that which can be folded fanwise beneath the firmer front region, and in many insects a similar arrange- ment is to be noticed. The radial, median and cubital nervures are often branched to a greater extent than in the grasshopper, five radial, three FIG. 8. WING-RUDIMENTS OF AN IMMATURE GRASSHOPPER, SHOWING TRACHIAL TRUNKS. Sc, sub-costal; R, radial {Rs, radial sector) ; M, median ; Cu, cubital; 1st A, first anal. After Comstock, “ Wings of Insects ”. or four median and two cubital branches being frequently recognizable (Figs. 35, 87). Between the longitudinal nervures fine transverse nervules are often developed in large numbers, and this condition is strongly marked in the grasshopper, whose wing-areas present the appearance of a complex network. The larger nervures contain blood-spaces and are traversed by air-tubes, outgrowths of the remarkable breathing-system of the insect that has yet to be considered. The growth of these air-tubes or tracheal trunks into the cavity of the develop- ing wing indicates the general course of the subsequently formed nervures (Fig. 8). 2