12a 



NOTES ON AFRICAN CHALCIDOIDEA— V. 



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



Imperial Bureau of Entomology, London. 



Eupelminus tarsatus, Waterst. (1916). 



Eupelminus tarsatus, Waterston, Bull. Ent. Res., vi, Feb. 1916, p. 389, figs. T 

 and 8 ; Lamborn, ibid., vii, May 1916, p. 34. 



A series of both sexes of this parasite of Glossina morsitans enables me to describe 

 the male for the first time and the female more fu'ly. One of the striking features, 

 about this species, apart from its remarkable sexual dimorphism, is the great range 

 in size which it exhibits. The females run from ^ mm. to 5 mm. and the males from 

 U mm. to 2| mm., with a range in the alar expanse of 2^ mm. to 3| mm. The larger 

 female examples are invariably darker and more metallic in coloration. Dr. Lamborn 

 is certainly right in correlating the smaller size of some of the parasites with a reduced 

 food supply il.c. p. 35). I cannot yet agree, however, that the parasitic status of 

 E. 'arsatus is definitely fixed by our present knowledge of its habits. Plainly the 

 proportion of Mwfi/^a-parasitised puparia supplied to the Eupelminus females was. 

 larger than could have occurred under natural conditions. Again, the factors, what- 

 ever they are, inducing Mutilla to oviposit in a particular puparium may be equally 

 decisive for the female Eupelminus. If, for example, in two cases three Eupelminus^ 

 punctures all close together could be seen with a high-power lens one might suggest 

 that some structural pecuharity invited the attack. Nor, incidentally, is it legitimate 

 to infer that because a puparium observed to be stung produced no Eupelminus the 

 attack had failed. The presumption is that the attack had not been delivered, 

 stinging and ovipositing being, in many cases, two separate processes. Many 

 Chalcids plunge the ovipositor into ova, puparia, etc., and then, applying the mouth 

 to the wound, suck up the contents which have been expelled. In other cases the 

 first stinging observed is merely the narcotising and rendering antiseptic of the host,, 

 which precedes the real introduction of the ova. The parasitic status of Eupelminus 

 can, in fact, be settled only by examination of puparia, collected under natural 

 conditions, from which the Chalcids have been noted to emerge. 



Additional Notes on the Female. 

 t 

 The most interesting fact revealed by Dr. Lamborn's new material is that the 

 female is sub-apterous. Examination of a number of specimens shows that in some 

 the fore wing (fig. 1) is present, in others the wing has broken off at the apex of the 

 axillary sclerite, while in others again the rupture has taken place below the tegula 

 itself. I am convinced now that the sclerite referred to in my original description 

 {I.e., fig. 8, T) is not the tegula but the exceedingly elongated axillary scutum which 

 fits into a groove running along the upper edge of the mesopleura. The hind wings^ 

 which are minute, fit into a similar depression of the metanotum. The axillary 



