( 251 ) 



XIII. Further notes on the terminal segments of Aculeate 

 Hymenoptera. By Edward Saunders, F.L.S. 



[Read March 5th, 1884.] 



Plate XIII. 



In the volume of our * Transactions ' for 1882 I made 

 some remarks on the terminal segments of the genus 

 Prosopis, and pointed out that good specific characters 

 were obtainable from an examination of the 8th ventral 

 segments of the ^ , as well as of the genital armature. 

 Since then I have extended my observations to the other 

 genera of the Anthophila, as well as to those of the 

 Fossores, Heterogyna, and Diploptera, and I find so 

 many interesting features disclosed by these examina- 

 tions that I thought a few remarks on them might be 

 interesting to the members of the Society. 



I may observe, in the first place, that the 8th ventral 

 segment is always distinctly present in the Aculeata, 

 and I have in several cases removed it entire, so as to 

 show the connection between the valves. As a rule it 

 varies more in form than the 7th, especially as regards 

 its ventral valve. It is the ventral valve of the 8th 

 segment which bears the three spines in Scolia, the up- 

 turned spine in Myzine and Methoca, and the spoon- 

 shaped apical process in Andrena and its allies; and yet 

 the presence of this 8th segment seems to have been 

 ignored by most hymenopterists, Klug and a few others 

 being the exceptions, or to have been mistaken for that 

 of the 7th, where this latter is hidden beneath the 6th, 

 as is the case in many genera, such as Pompiliis, 

 Andrena, &c. In many others the 8th segment is 

 entirely hidden, and can only be observed after dissection ; 

 but even then, as in Prosojns, it exhibits great variety of 

 form ; there is one character whereby the ventral valve 

 of the 8th may in most cases be known, viz., that it is 

 produced basally in the centre, whereas the 7th is only 

 produced basally at the sides. The dorsal valve of the 

 8th is generally more or less membranous or corneous, 



TRANS. ENT. SOC. LOND. 1884. — PART II. (jULY.) 



