BY R. J. TILLYARD. 463 



tion in size, and by the backward shift of the second ante- 

 nodal. This latter movement in itself may have preserved 

 the inferior sector from further reduction, by preventing the 

 tendency to increased petiolation. Probably, also, the con- 

 traction of the southern land-masses to their present rather 

 small dimensions, has been a very great fa,ctor in inducing 

 asthenogenetic specialisation in this and other groups. 



31. Hemipiilebia mikabilis Selys. (Plate xlix., fig. 21.). 



Selys, I DC. cit., p. 64. 



cf. Appendages: superior 0-8 mm., very slightly for- 

 cipate, bronzy-black above, creamy beneath ; in profile, the 

 tips are flattened and pointed; inferior 11 mm., flat and 

 wide, appearing narrow and slightly waved from above, but, 

 in profile, thick and doubly curved like a flat S ; structure 

 delicate and almost ribbon-like ; creamy-white, with delicate* 

 soft hairs (Plate xlix., figs. 6, 7). 



I do not think that the real use of these remarkable ap- 

 pendages has yet been recorded. At Alexandra, Victoria, 

 the only locality where I have met with this species, I found 

 it sitting about in the dense reed-masses that grow in and 

 around the backwaters of the Goulburn River. It flew but 

 seldom, and then only to pass from one reed to another close 

 by. The male has the remarkable habit of walking slowly 

 up a reed-stalk, raising the end of its abdomen, and waviny 

 it U'p and down two or three times fairly quickly, at the same 

 time disjdaying the white ribbon-like inferior appendages 

 very consjnciiously. Always, after a short flight, this was 

 done ; and again, when the sun came out after a passing 

 cloud or rain-squall, these insects would begin to climb the 

 reeds again, and repeat the performance. Owing to their 

 colouration, it was almost impossible to detect these tiny 

 insects on the dark green reed-stems, had. if not been for this 

 habit; and I soon began to watch for the display of the white 

 appendages, and by this means secured a number of males. 



