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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



developed ; the brachypterous or short-winged form, on the contrary, 

 has both pairs of wings reduced and nonfunctional. The long-winged 

 specimens are perfectly able to fly and they do so, especially at night 

 when attracted by lights. They do not, however, fly readily in the 



I M R Sc C 



Rl Rs M VD 



\ \ \ \ 



ICu 2'Cu 3A ik lA 

 2Cu ICu R+N Sc C 



Fig. 10. — The wings of MarcUia remipcs. 



A, left fore wing, or tegmen. B, left hind wing. 



lA, 2A, sA, gA, first, second, third, and ninth anal (vannal) veins ; 3 Ax, third 

 axillary sclerite ; C, costa ; iC\i, 2Cu, first and second cubitus ; iCV , first con- 

 cave anal vein ; /, intercalary vein ; M, media ; R-\-M, united basal shafts of 

 radius and media; R, radius; Ri, first branch of radius; Rs, radial sector; SAV, 

 secondary anal vein of first anal plait ; Sc, subcosta ; VD, vena dividens. 



daytime, and when disturbed or chased they usually escape by swim- 

 ming and submerging as the flightless forms do (Carbonell, 1957). 



The tegmen of Marellia remipes (fig. 10 A) is narrow and has a 

 pronounced marginal lobe in the costal area, near the base of the wing. 

 When the wings are flexed, this lobe covers the tympanal organ and 

 the first abdominal spiracle, and its development might be related to 

 underwater breathing as we shall see later with respect to the ab- 

 dominal spiracles. 



