BY FREDERICK A. A. SKUSE. 143 



much arcuated ; anterior branch indistinct, very little bent. 

 (Description drawn from dried specimen). 

 Mab. — Middle Harbour (Skuse). 



B. Wings with five longitudinal veins ; the third furcate ; the 

 fourth and fifth sepaiate from their base. 



Genus 2. Tritozyga, Loew. 



Tritozygi, H. Loew in O.-Sacken, Mon. Dipt. N. America, 1862, 

 pp. 178-179. 



Antennae as in the last genus, the number of joints uncertain. 

 Wings rounded at the base and apex. Second longitudinal vein 

 running rather close to the costa and joining much before the apex 

 of the wing; the upper branch of the third longitudinal vein forming 

 a double curve, almost in the shape of an S (PI. iii., fig. 21). 



Obs. — This genus was founded by Prof. Loew upon an imperfect 

 specimen of a North American species, and no further example 

 ha.s to ray knowledge since been observed in any country. The 

 whole structure of the body of this insect, according to Prof. 

 Loew, shows the nearest relation to Campyloviyza. 



Genus 3. Catocha, Haliday. 



CatorJui, Haliday, Eut. Mag. I., 1833, p. 156 ; Macquart, S. k B. 

 IL, 1835, p. 654 ; Rondani, 11''* Mem. Parma, 1840, kc. ; Win- 

 nertz, Stett. E.Z. VII, 1846, p. 20 {Macroatyla) ; V. z.-b. G. Wien, 

 1870, p. 27; Walker, I.B. III. 1056, p. 59; O.-Sacken, Mon. 

 Dipt. X. America, 1862, p. 177; Schiner, F.A. IL, 1864, p. 412. 



Antennae Dioniliform, verticillate ; in the ^ 2-+ 14 , and in the 

 $ 2- -»- 8-jointed, the flagelhtr joint iiImostov;ito ; jjediccls longer in 

 the (J than the $ ; the first joint .sessile. Wiugs largo, considtT- 

 ably rounded at the apex, with cuncifotm base. First longitudinal 

 vein long, arcuating into the costa somewhat abruptly ; second 

 longitu<linal vein reaching the margin about the apex of tlio 

 wing ; the upi)er branch of the third longitudinal vein forming a 

 smooth curve ; small cross-vein at or Ixifon; the middh- of tlio 

 firKt longitudinal vein (Pi. ill., fig. 22). 



OIb. — Only a few European species known. 



