274 AUSTRALIAN PSYLLID.r., 



The extraordinary form of the fish-like larv?e of the species 

 living upon the Casuarina, shows how they adapt themselves to 

 the slender thread-like foliage upon which they live. Scott has 

 described several South Amenican species producing galls, and 

 Buck ton recently described one from India, and though he 

 figures the wings as those of a Trioza, he places it in the genus 

 Psylla. 



Trioza orbiculata, n.sp. 



(Plates XV., fig. 9; xvi., fig. 22.) 



Pupa large, broad; dorsal surface black, fringed right round 

 with fine ciliated spines ; ventral surface pale green, legs and 

 antennae black. Back flattened ; head and thorax forming a 

 rounded shield twice as large as abdomen. 



Imago. — Length 0"11, antennae 0*03 inch. 



General colour brownish-yellow; eyes reddish-brown; abdominal 

 segments darker, banded with fuscous; wings hyaline, nervures 

 light brown. Head narrow, nearly as broad as the thorax, deeply 

 impressed in front, with a deep median suture, and large fovea 

 on either side wrinkling up all the front of the forehead; hind 

 margin deeply arcuate. Face lobes small, fringed with long 

 hairs. Antennae very long, slender; lst-2nd stout; 3rd-9th long, 

 slender; 10th short, slightly clubbed. Eyes large, projecting, 

 rounded on outer margin, deeply angled on inner nuirgin : central 

 ocellus hidden at apex of median suture; lateral ocelli large, in 

 line with centre of eyes. Thorax : pronotum very narrow, curved 

 upward, swelling out behind eyes; dorsulum very large, convex, 

 projecting and rounded in front, sloping sharply on sides, which 

 are rugose and slightly toothed, apex truncate; mesonotum large, 

 curving round dorsulum on sides, truncate in centre, at base and 

 apex; scutellum large, truncate in front, convex, rounded behind. 

 Legs short, stout. Wings nearly thrice as long as broad; long, 

 slender, more rounded at tips than usual ; primary stalk long, 

 turning slightly upward; stalk of subcosta very short, no costal 

 cell or stigma; radius short, turning up, forming a lanceolate cell, 

 stalk of cubitus wanting; upper branch of cubitus first turning 



