Pipunculus. 41 



be distinguished without difficiilty; with regard to tlie females varipes 

 is known by the shining thorax, pale legs and somewhat strongly 

 recurved ovipositor, spinipes has a less shining, sometimes nearly 

 quite dull thorax, dark legs and ovipositor straight or nearly so, 

 and longer than the basal part, Thomsoni and ater with their dull 

 thorax are besides known from spinipes by the ovipositor being 

 shorter and the legs generally darker, and as before said they are 

 distinguished from each other as Thomsoni has a quite grey frons and 

 a longer, nearly straight ovipositor, while ater has the frons black 

 above and a shorter and a little recurved ovipositor. — For the three 

 last named species I have followed the synonymy given by Becker 

 in 1915, which corrects that in the Cat. Dipt. 1910 and certainly 

 comes as near to the truth as at present possible. Only with regard 

 to Zetterstedt's pratoriim it seemed to me that we could not be sure; 

 Zetterstedt describes ater with an abdomen which is different in the 

 two sexes, shining in the female, but with dull bases of the segments 

 in the male; for the other two species, pratorum and campestris he 

 on the contrary gives a shining abdomen without sexual difference, 

 and the differences he otherwise mentions are small and of no con- 

 sequence; further he says under pratorum that he had got this species 

 from Stæger under the name of campestris, and campestris in Stæger's 

 collection is spinipes; I therefore think that it might be thought 

 rather probable, that Zetterstedt's pratorum was also spinipes and 

 not Thomsoni. I have, however, had opportunity to see Zetterstedt's 

 specimens of the four species in question; varipes and ater are identical 

 with our interpretation; pratorum is in my opinion our Thomsoni, 

 but with regard to campestris Zetterstedt has confused this species 

 and pratorum; a male and a female are campestris (our spinipes), 

 but two pairs, each pair pinned on the same pin, are in my opinion 

 Thomsoni; Zetterstedt has thus not laid sufficient stress on the male 

 abdomen, whether being shining or with velvet bands. It is curious 

 that Zetterstedt has confused spinipes and Thomsoni, while we should 

 more probably have waited him to mix the very similar Thomsoni 

 (his pratorum) and ater. 



The two impressions on fifth abdominal segment mentioned for 

 Thomsoni and ater might be thought to be due to exsiccation, but 

 they are always present; they belong, I think, to the same category 

 as the depressions mentioned by Perkins (Rep. of Exper. Stat. of the 

 Hawaiian Sugar Plant. Ass. 1901, Bull. 1 Part. IV, 127). 



