DESCRIPTION OF THE SPECIES. 239 



and to describe as, for instance, the majority of the European 

 Urophorae. It is only by observations upon the insect in life, 

 that the question will probably have to be solved, whether we 

 have here different species or only varieties. In writing the first 

 part of these Monographs I surmised that I had specimens of a 

 single, but very variable species before me. In the mean time 

 my materials have increased considerably, and specimens have 

 been added to it, which differ so materially from the typical T. 

 longipennis, that my former conviction has been shaken, without, 

 however, having been superseded by the opposite one. I prefer 

 therefore to continue to treat these different forms as varieties 

 of the same species, but, at the same time, to define these 

 varieties with more precision than has been done in the first part 

 of the Monographs. In order to avoid useless repetitions, I will 

 notice in advance that in all the varieties the anterior end of the 

 middle stripe is colored black, and that in all of them, immedi- 

 ately above the root of the wing, there is a small, deep-black dot, 

 which is not visible when the wings are folded. 



1. Varietas perfecta, % ?. — Of the four lateral bristles of the 

 front, the two upper ones, in the male, are very much incrassated 

 and truncated at the end. Thorax without black lateral stripes. 

 Scutellum unicolorous ; metathorax without black picture. Picture 

 of the wings not very deep in its coloring, complete in both sexes; 

 the male as Tab. X, f. 2. 



Of this variety I have compared rather numerous specimens. 

 Among those of my collection there is a male and two females, 

 caught at the same time. 



2. Varietas typica % <?. — Of the four lateral bristles on the 

 front the two upper ones are very much incrassated in the male 

 and truncate at the end. Thorax without black lateral stripes ; 

 scutellum upon each lateral corner with a well-defined black spot. 

 Metathorax without any black coloring. The picture of the 

 wings is of a rather dark shade, especially towards the tip; com- 

 plete in the female, incomplete in the male, almost like Tab. X, f. 

 2, except that the rivulet covering the posterior crossvein does 

 not reach the margin of the wing, but gradually becomes more 

 attenuated and pointed and never reaches beyond the posterior 

 end of the posterior crossvein ; the branch of this rivulet which 

 runs along the last section of the fourth vein is likewise very 

 narrow and always disappears at a considerable distance from 



