784 DIPTERA OF AUSTRALIA, 



Three species belonging to this genus have been described, two 

 occurring in Europe and one in North America ; and according to 

 Baron Osten-Sacken the genus also occurs in New Zealand. All 

 known species exhibit a wonderful similarity and are difficult to 

 separate ; the wings are marked with numerous ocellate spots 

 which vary little more in the different species than they do in 

 individuals. 



Prof. Mik (Verh. z.-b. Ges. in Wien, XXVIIT. p. 617, 1879) 

 discusses the described species, and establishes the distinction 

 between the two European species by the structure of the male 

 forceps and character of the wing- markings. 



The species now described from Australia seems more closely 

 related to T. ccasarea^ O.-Sack., than to annulata. Linn. They agree 

 very well in the picturing of the wings, except that T. australis 

 has not the marmorated second basal cell so characteristic of 

 Gcesarea. The auxiliary vein (judging by Prof. Mik's figures) is 

 not so long, the second longitudinal vein is more arcuated, and 

 the third longitudinal vein more strongly converges towards the 

 fourth. On the other hand, the structure of the holding forceps 

 is more like that of T. annulata, possessing the rostriform ap- 

 pendage; it differs, however, in having the upper margin of the 

 anal segment emarginate, and not dentate as in both European 

 species. 



310. Trochobola australis, sp.n. (PI. xxi., fig. 7). 



J. — Length of antennae 0*070 inch ... 1*77 millimetres. 



Expanse of wings 0-340 x 0*080 ... 862 x 2*02 



Size of body 0*250 x 0*030 ... 6*34x0*76 



Head, including rostrum, palpi and antennae, black. Collare 

 ochreous-yellow. Thorax ochreous-yellow, almost covered with 

 three broad brown stripes, levigate ; pleuree and metathorax dark 

 brown; scutellum deeply bordered with brown. Halteres brown, 

 the club and base of stem pale. Abdomen brown or brownish- 

 ochreous (greenish-yellow while living), the first segment ochreous 



