231 



NOTES ON AFRICAN CHALCIDOIDEA— III. 



By James Waterston, B.D., B.Sc, 

 Imperial Bureau of Entomology, London. 



It cannot be said that any satisfactory division of the Tetrastichini has yet been 

 proposed. With the exception of one or two easily recognised groups like Melittobia, 

 Westw., Crataepiis, Forst., and Hyperteles, Forst., the genera are ill-defined, and this 

 is specially the case with Tetrastichus, Hal., and its immediate allies. It has become 

 evident that the mesonotal furrows or impressed lines have not the value for 

 diagnosis that many writers have assigned to them. Recently Kurdjumov (Revue 

 Russe d'Entomologie, xiii, p. 246, 1913) has separated Tetrastichus from Geniocerus, 

 Ratz., by the chaetotaxy of the sub marginal, assigning to the former genus those 

 species which have one, and to the latter, species with more than one bristle in 

 this position. Such a division, I believe to be unnatural, as it is certainly 

 inconvenient.* In the following descriptions I have included one species in 

 Tetrastichus though it has more than one bristle on the submarginal. I think 

 it impossible, in the present state of our knowledge of the Tetrastichines, to say 

 what characters are of basal importance. For grouping species, the funicle (shape, 

 segments and chaetotaxy), the position of the scrobes, the shape of the pronotum 

 (especially whether straight-edged or emarginate posteriorly), the chaetotaxy 

 of the meson olum and the propodeon, give generally the most reliable clues, 

 while specific characters appear to lie in colour, proportions and chaetotaxy 

 of the wings. How far the ring joint can or should be used is doubtful. When 

 consisting of a number of equal rings it may be of some assistance, but in other 

 cases, \he basal ring is much the greatest, and it is almost impossible to say whether 

 the succeeding lamina is distinct or not. Even with an oil immersion difficulty may 

 be felt, and there is the further question of the morphological equivalence of these 

 laminae. In the present paper four species assigned to Tetrastichus are described ; 

 of these, three are grouped together, mainly on account of antennal and propodeal 

 characters, the fourth I have placed with some others described from dipterous hosts, 

 but if the absence of whorls of hair from the male funicle proves to be more fundamental 

 than the antennal coloration and the propodeal sculpture, possibly all four should go 

 together. In describing the antennae, details are given of the sensoria, which, though 

 rather variable in number on any individual joint, are more constant for the funicle 

 and club as a whole. 



The following features are shared by Tetrastichus atriclavus, T. sculpturatus and 

 T. mauripennis, spp. no v. 



(J $. Wings more or less tinted ; propodeon with median keel and pleurae ridged 

 superiorly below the notopleural edge. The whole notum strongly raised reticulate 

 or honeycombed ; spiracle opening on the pleura outside the notopleural edge, 

 surrounded by a hollow or sulcus which is distinct posteriorly. 



(J. Scape with a large sense organ, fringed ventrally with long hairs. Funicular joint 

 without any long basal or sub-basal whorls of hairs ; antennae pale^ except the dark club. 



?. Antennae dark, except scape. 



*Gf. Crawford, Proc. U.S. Nat. Miis., xlviii, p. 584, May 1915. 



