7. PTIOLINA 309 



Wings (fig. 202) with a true Leptid venation, but the cubital fork long and 

 almost straight-sided (not bell-mouthed) starting with an acute angle and witJi its 

 upper branch enchng well before the tip of the wing but much nearer to the lower 

 branch than to the radial vein, while the lower branch ends at the tii) of the wino- • 

 the two upper veinlets from the discal cell start close together and sometimes even 

 from a common pedicel (figs. 204, 205), but this character is very variable in individual 

 specimens (and even m individual wings), and in one or two females (fig 206) the 

 divergence apparently begins in one wing before the end of the discal cell • radial 

 vein curving upwards to the costa so as to margin the long dark stigma • discal 

 cross-vein placed on the basal quarter or third of the discal cell ; anal cell' closed 

 bquanicB (alar) large and bearing a fringe single-rowed on the lower part but manv- 

 rowed on the upper part. 



The first author to realise that there were several closely allied species 

 of PHolina was AVahlberg, who (Vet. Akad. Forhandlingar, 1854, p. 214) 

 described with care four Scandinavian species in both sexes, and if our 

 commonest British species is among them it must be the one described as 

 PL obscura Fallen. Since then no doubt has ever arisen as to the limits 

 of the genus unless over Simnia, but considerable doubt has arisen about 

 the identification of the European species. 



This genus contains only four or five well-recognised European species 

 but about as many more doubtful ones ; some of' them are said to have 

 occurred at times in large numbers among reeds {Arundo), but P. obscvra 

 has usually occurred in rather dry places. It appears to be probable that 

 the species sometimes occur in considerable numbers for a very short 

 period. 



Most of the species occur in Northern Europe, but records are o-iven 

 of one from Italy and three from Canada. ° 



Table of Species. 



1 (2) Antenna almost bare on the two basal joints (fig. 200). Side-cheeks 

 sparsely pubescent. 1 obscura. 



Fig. 200.-P«oZmao6scMra (J. x 48. Fig. SOl.-PitoZwta a«ra <J. x 48. ' 



2 (1) Antennae with long hairs on the basal joints of the male (fig. 201) 



and with short hairs in the female. Side-cheeks bare. 2 atra 



(nif/ra Zctt.). 



^^ra/jH?/ — Zetterstedt described the genus '' Ptiolina Stajg." in 1842 for Leptis 

 obscura of J^ alien and a new species Pt. nigra Stajg. in litt. ; the generic characters 

 given on page 21 of Diptera Scandinavia?, vol. i., sufiiciently define the genus, but 

 the characters given on page 226 are useless. From the very beginning the ^enus 

 seems to have suftered from synonymical troubles, and although Fallen's species may 

 Have been well recognised by North Europeans it has been much misunderstood 

 or incorrectly described by others; Pt. nigra started in 1842 with the following 

 synonymy : ° 



Ptiolina nigra Stager in litt. 1838. S. 



Lefptis nigriiia n. sp. ? . Wahlb. Observationes Dipterologicaj in Manuscr. 

 Leptis obscura var. specimina Darlecarlica Zett. Ins. Lapp. 527, 7. 

 b2)ama atra Stteg. in Htt. receutioribus Hafniae 6 Nov. 1841. 



