1903.] 233 



are well known to all students of the wasps. The shins of the latter (Plate, fig. xi) 

 are clothed with long hairs not found on those of the former (Plate, fig. 11) ; and 

 in the female, as pointed out by Thomson ('7-4), the tarsal segments are broader in 

 V. austriaca than in T'. rufa* The basal segments of the abdomen in V. rufa 

 (figs. 12 — 15) are broader than in V. austriaca (figs, xii — xt). The male armature 

 in V. rufa (fig. 6) is broader and darker than in V. austriaca (fig. vi), while the 

 ear-shaped process at the end of the stipes has a characteristic form in either 

 species (compare figs. 8, viii). The face of V. rufa has a central black anclior mark, 

 and a rather small and narrow yellow crown mark is found on the black area above 

 (fig. 1), while in V. austriaca the " crown mark " is large and deep, and the face, 

 almost immaculate yellow (fig. 1) in the male, shows in the female three black 

 specks of varying size (see Cuthbert's figures, 97b). Moreover, the clypeus of V. 

 austriaca is decidedly concave on the lower edge (figs, i — v). The scape of the 

 feeler is black in the female of V. rufa, and often in the male also (fig. 1), while in 

 V. austriaca it has a strong yellow patch in both sexes (figs, i, iii, iv). The black 

 abdominal markings of V. rufa are edged by ill-defined reddish areas (fig. 12), 

 while those of V. austriaca stand out clearly from the lemon-yellow ground colour 

 (fig. xii). The puncturation of F. rufa is coarser than that of V. austriaca. 



Examination of the large series of these wasps that have passed through our 

 hands shows that most of these characters are fairly constant. In no case have we 

 found any wasp that can be considered as exactly intermediate between V. rufa and 

 V. austriaca — none that could give rise to hesitation as to which of the two forms 

 it sliould be placed with. But we have found a number of specimens of V. rufa 

 that show very marked variation in the direction of V. austriaca, and a smaller 

 number of specimens of the latter that approach in some respects towards F. rufa 



Three characters only seem to be absolutely distinctive : — (1) The shins of F. 

 austriaca are always hairy ; those of F. rufa never. (2) The male armature of 

 V. rufa is always, as Robson has pointed out ('98), more robust and darker than 

 that of F. austriaca. (3) V. rufa has the integument more coarsely punctured. 

 All the other characters show more or less variation in different individuals of the 

 two forms, and some of the most striking of these variations will be found figured 

 on Plate. 



Taking, in the first place, the head-markings, a black anchor-mark on the face 

 (fig. 1) characterizes F. rufa, while the male of F. austriaca has typically an un- 

 spotted yellow face (fig. i) which shows only the slightest traces of the black dashes 

 that characterize the female. But very extensive variation is to be noticed in both 

 forms. Tiie anchor-mark of F. rufa may not reach the edge of the face (fig. 2), or 

 it may become reduced to a central patch (fig. 3), to three minute touches (fig. 5), 

 or to a terminal trident mark (fig. 4). Then, in certain examples of V. austriaca, 

 we find that the face shows black marks like those of the aberrant rufa males just 

 mentioned (compare figs. 3, 4, 5, with figs, iii, iv, v). Moreover, in some of these 

 aberrant rufa males, it will be seen that the yellow crown-mark above the face is 

 larger than usual (figs. 3, 5), while in the aberrant austriaca males it is sometimes 

 smaller than usual (fig. v). The edge of the face also is less markedly concave in 

 the black-spotted austriaca forms (fig. iii) than in the normal immaculate specimens 



* But Thomson's statement (writing of V. ri</«), " tarsis multo angustioribus," seems to us 

 too strongly expressed. 



