10. BERIS 199 



conspicuous dark stigma wliicli lies between these two veins ; cubital vein practically 

 straight and emitting its fork at about lialf its length, and ending distinctly before 

 the tip of the vnng ■ discal cross-vein close to the origin of the cubital vein and 

 placed near the middle of the discal cell ; discal cell emitting two veinlets from 

 its end which are rather approximated at their origin and which extend to the wing- 

 margin, and sometimes an abortive third veinlet (fig. 150) or a trace of one may occur 

 (not necessarily alike in the two wings), and as there is no small cross-vein the last 

 part of the upper branch of the postical fork appears to issue from the lower part of 

 the discal cell ; the upper branch of the fork of the postical vein forms the lowest 

 side of the discal cell for a short distance, and the lower branch bends down rather 

 abruptly and joins the anal vein considerably before the wingmargin ; wing- 

 membrane minutely pubescent all over but not at all ribbed or rippled. Alar 

 squamae moderate in size and with a delicate moderate fringe ; thoracal squamae 

 only represented by the frenum. Halteres normal. 



The metamorphoses of the restricted genus Beris are very little known, 

 and I can only record that B. chalyheata. has been bred from moss, 

 but those of Chorisops tibialis have been described in detail The perfect 

 insects usually occur on shrubs in the vicinity of water, and Colonel 

 Yerbury has seen the males dancing with a rather wild flight. 



This genus is allied to Adina and Chorisops, but is distinguished from 

 both of them by its obsolete palpi and by the touching eyes of the male, 

 while Chorisops is fuj-ther distinguished by its bare eyes. B. Morrisii is 

 however very near to Chorisops. 



Beris (including Adina and Chorisops) is a genus which has a very 

 wide range, as species are known from South-west Asia, North, Central, 

 and South America, Australia, and probably New Zealand. The European 

 species are few in number, there being only five or six species of Beris, 

 one of Adina, and one of Chorisops, all of which occur in Britain with the 

 possible exception of the Adina ; Bonsdorff was unable to record any of 

 them from Finland. 



Synonymy. — Beris was intelligibly founded by Latreille in 1803, with Stratiomys 

 sexdentata F. given as the type, and with a remark that the genus was probably tte 

 same as " Les potamides " of Meigen. There was a genus Potmnida suggested by 

 Meigen in 1800 in his " Nouvelle classification des mouches a deux ailes,"but that 

 work was always treated by Meigen himself as a mere undeveloped suggestive paper 

 and not as a scientific work. Beris sexdentata F. is a synonym of B. chalyheata 

 Forster, and tlierefore that species must be accepted as the type of any restricted 

 genus Beris. In 1804 Meigen well founded a genus Actina which was equivalent to 

 Beris (sensu lata), and as his first species, A. chalybea, was a synonym of A. nitens 

 that fact may constitute A. nitens as the type of Actina, more especially as all the 

 other species then kno^vl^ had been previously included under Latreille's name Beris. 

 In 1820 Meigen sank his genus Actina under Beris. and Loew supported this 

 action in 1846 even though Curtis in 1830 had expressly applied Meigen 's name 

 of Actina to B. tibialis on the grounds of the generic value of its long palpi, 

 eyes not contiguous in the male, wings with an additional nervure, and posterior 

 tibiae incrassated ; Curtis was wrong in applying the name Actina to B. tibialis 

 because the genus Actina was founded in 1804, while the species tibialis was not 

 even described until 1 820, but his distinctive characters were good ; next Haliday in 

 Westwood's Inti-oduction to the Modern Classification of Insects, vol. ii., Syn. 130 

 (1840) separated the two genera as follows : 



" 5ms Latr. Scutellum 6- or 8-spined ; antennae 10-jointed ; eyes contigTious ^ ; 

 " palpi obsolete. 



"Actimi Meig. Scutellum 4-spined ; palpi long ; eyes apart in ^ ." 

 It is now known that the number of spines on the scutellum is not even of 

 specific, much less generic, value. Schiner in 1862 reaffirmed the genus Actina for A. 

 tibialis and A. nitens, but previous to this Eondani had in 1856 suggested a genus 

 Choriso2)s for Beris tibialis Mgn. on very insufficient characters, though the name 

 Chorisops showed that he had appreciated the character of the separated eyes of the 



