14 



BRITISH ANTS. 



Of these three pairs of appendages the stipites enclose the volsellae 

 and the latter enclose the sagittae and spatha. 



The Subgenital Lamina is a plate situated beneath the genitalia, 

 and forming in fact the ninth ventral segment of the abdomen. 



Fig. 26. 



Sagittae Spatha 



genitalia of Formica rufibarbis (dorsal). 

 (Donisthorpe. ) 



It is sometimes pointed, forked, or rounded, and presents valuable 

 distinctive characters in some genera. 



Finally there are a small pair of hairy appendages, the Penicilli, 

 which are attached to the tenth dorsal segment of the abdomen. 

 They are not present in some genera such as Anergates, Dorylus, 



Volsella 



Stipes 



Sagittae 



Fig. 27. <? genitalia of Formica rufibarbis (ventral). 

 (Donisthorpe.) 



etc. ; and in Prenolepis they are present in some species, and 

 wanting in others, and are consequently valuable for classification 

 purposes. They are stated to represent the Cerci in Blatta (the 

 " Cockroach "), etc., but this does not seem to be absolutely certain. 

 The sting is retractile, and its size, in different species, varies 

 greatly, not always in proportion to the size of their bodies. It con- 



