82 l^^P"^' 



7. Stigma unicolorous-yellow vesicator, Brerai. 



{■vesicator, togatus, C). 



— Stigma white, with the apex more ov less infuscated 8. 



8. Very small ? (about 3 mm. long) with exceedingly long saw-sheath," longer than 



the belly" (Konow), '* terebra et cercis longissimis " (Thoms.). Femora 

 generally clouded beneath. Ventral surface quite black, except the naiTOW 

 basal part of the saw-sheath, which is yellowish. (I do not know the $)... 



proximo, Lep. 



= dolicJiurus, Thoms. 



{gall I cola, herhacese, alhicarpus, C). 



— Larger species (4 — 5 mill, long) saw-sheath of ? shorter, but still long — occupying 



at least half the ventral surface 9. 



9. Femora for the most part black .femoralis, Cam.* 



{ixchnocerun, C , nee Thoms.). 



— Femora quite pale l^X 



10. Transverse frontal ridge (midway between ocelli and insertions of antennae) 



thick, obtuse, interrupted by a narrow longitudinal sulcation across its 

 middle. (Common species, very variable in colour, according to Konow, and 



desciibed under many names) salicis, Christ. 



{interstitialifi, salicis cinerex, vacciniellus, C). 



— Frontal ridge narrow, sharp, and unbroken hella, Andre. 



{hella, haccarum, C). 



Nematus, L. (sec. Knw.). 



The group of species to which the generic name Nemaius is con- 

 fined in Konow's system is remarkably uniform and distinct. They 

 are all about of the same size (6 — 7 mm. long). The $ $ may be 

 known at once by the fact that their last ventral segment is not, as in 

 other Nematids, drawn out into the form of a narrow triangle, but 

 broadly truncated, so that it ends not in a point nor nearly so, but in 

 a long transverse line which is even more or less sinuated inw^ards, 

 though the convexity of the segment makes this sinuation a little 

 difficult to realize except in particular points of view. The $ $ have 

 an equally striking character in the great development of the saw- 

 sheath. This, viewed laterally, is excessively long, and, viewed dorsally, 

 excessively broad — at the base in all the species, and in all but one at 

 the apex also. In some cases the stigma has a very peculiar coloration, 

 yellow with a dusky base. The third cubital cell is commonly long 

 and parallel-sided. The ground colour of the body in all our species 

 is luteous or testaceous, varied to a greater or less extent (especially 

 above) with black. 



Eour British species are known to me, and these are easily dis- 

 tinguished. They are the same which Thomson records from Scandi- 

 navia, and may be tabulated as follows : — 



* Described in Fauna Scot., 1878. In the Monograph it is called ischnocerus, Thoms., but 

 according to Konow, it is not that species. (I do not know it except from the descriptions). 



