l84 HYMENOPTERA ACULEATA. 



the apex, the sagittae short and subtriangular ; legs with 

 the apices of the femora, the entire tibite and tarsi in the S ) 

 with the exception occasionally of a black spot inwardly, 

 the base of the tibise only in the ? , yellow. 



L. 5-6 mm. 



July and August ; Hastings ; Hayling Island, on Uier- 

 aceiim and Etipliorlici. Walmer, on Achillea abundantly. 



I find I have been quite wrong in referring the above 

 species, which I have taken freely in several localities, 

 to dilatafa, Kirb., of which I have carefully re-examined 

 the type in the British Museum ; I cannot find any de- 

 scribed species with which it will agree, I have therefore 

 named it in honour of Dr. Mason, of Burton-on-Trent, to 

 whom I am greatly indebted for the loan of the specimens 

 from Smith's collections, which have enabled me to verify 

 the synonymy as regards the species described by him. 

 This cannot be liinhi Gorski, as that species has the 

 apices of the posterior tibise black and the antennae with 

 rings of a darker colour, and, according to Thomson, the 

 third abdominal segment beneath transversely tuberculated. 



P. dilatata, Kirh., Smiih {nee Saunders). — The S of this 

 species diffei's from that of Masoni in the absence of the 

 dark apex of the antennfe, and in the shape of the scape, iu 

 which the anterior and posterior margins of the dilatation 

 are subparallel, so that it is almost four-sided, the dilatation 

 being produced upwards beyond the apex of the stem of 

 the joint, instead of diverging from it at right angles; the 

 front of the dilatation is pale, the colour widening above, 

 the mandibles are yellow ; the pronotal collar has two yellow 

 spots, the mesonotum is narrower and not quite so closely 

 punctured, the postscutellum is wider and the propodeum 

 more coarsely clathrate ; the abdomen is much more finely 

 punctured, and rather more densely clothed with pale 

 Lairs, esj^ecially laterally at the apices of the segments, 

 the edges of the segments slightly discoloured, beneath 

 almost impunctate, fourth and fifth segments raised trans- 



