378 MEDICAL ENTOMOLOGY 



been freely used : also Newstead's important papers on the structure of 

 the male genitalia, and Roubaud's thesis on Glossina palpalis. one of 

 the most important works on the subject. Other papers in the Bulletin 

 of Entomological Research have also been consulted, as well as the sum- 

 maries of recent work in the Sleeping Sickness Bulletin and in the 

 Tropical Diseases Bulletin. 



In classifying these muscids Newstead's scheme, which is based 

 on the structure of the male external genitalia, will be followed. This 



observer rightly says that the structure of the external 

 Classification of the . ,. ", ,V u -j ^u re v * 



Glossininae genitalia must be the best guide to the affinities exist- 



ing between the several species. A description of the 

 external genitalia of Glossina is given on pages 87 and 88. 



NEWSTEAD'S KEY TO THE SPECIES OF GLOSSINA 



Newstead divides the genus Glossina into three groups as follows : 



Group 1. THE FUSCA GROUP. In this group are placed the seven 



largest species of the genus; G. fusca, Walk., G. nigrofusca, Newst., G. 



tabaniformis, Westw., G. longipennis, Corti, G. brevipalpis, Newst., G. 



medicorum, Aust., and G. severini, Newst. In these species the superior 



claspers are entirely free, and have no membrane between them ; their 



distal extremities have either a single large blunt tooth-like extension, 



or they are bluntly bidentate ; the harpes present differences in structure 



in all the species. 



Group 2. THE PALPALIS GROUP. The following species are placed 

 in this group : G. palpalis, R.-D., G. calignea, Aust., G. tachinoides, 

 Westw., G. fuscipes, Newst., and G. pall ice ra, Bigot. In these species 

 the superior claspers are connected by a delicate spinose membrane 

 which is deeply divided in the middle, but the distal extremities of the 

 claspers are free and widely separated. 



Group 3. THE MORSITANS GROUP. This group contains the 

 following species : G. morsitans, Westw., G. siibmorsitaiis, Newst., 

 G. pallidipes, Aust., and G. longipennis, Wied. In these species the 

 superior claspers are completely united by a spinose membrane, and 

 are also fused in the middle line ; they are highly complicated, and 

 Newstead compares their shape to that of the scapula of a mammal in 

 miniature. 



Utilizing the above differences in the structure of the external genitalia, 

 Newstead gives the following key for the identification of the species. 



Group 1 (Fusca Group). Large species, length exclusive of proboscis 

 lOf to 12 mm. 



