50 [March, 



Prosopis palustris, sp. nov. 



(? . Blaok, abdomen shining. Face below the antennge entirely yellow, and at 

 the sides this colour is continued backwards broadly along the borders of the eyes 

 for some distance above tlie insertion of the antennae. Front tibiae pale outwardly, 

 the middle pair narrowly at the base, the posterior on their basal half. All the 

 metatarsi pale, as well as the prothoracic tubercles. Labrum and mandibles black. 



Face moderately long, and with the eyes convergent towards the apex, distinctly 

 and widely impressed on each side, above the antennsB very densely punctured and 

 clothed with short grey hairs. Basal joint of the antennae about twice as long as 

 wide, its hind margin rounded, and fringed with grey hairs, beneath distinctly but 

 not very strongly arched. Mesothorax and seutellum densely punctured. Anterior 

 area of the propodeum with very strong transverse rugosities, the rest with dense 

 irregular rugosity and clothed with grey hairs. Abdomen with the basal segment 

 very shining, impunctate, or with a faint trace of obsolete punctures, and with a 

 little grey pubescence at the apex laterally in fresh examples. Second and third 

 segments with iine indefinite puncturation, and clothed with short grey inconspicuous 

 hairs, rather longer and more distinct along the apical margins, which are impressed 

 and even very slightly reflexed. Terminal (8th) ventral segment produced at the 

 apex into a long erect process, which is clothed with hairs on the apical portion. 



$ . Black, a large triangular space on each side of the face ; the prothoracic 

 tubercles, a spot at the base of the front and intermediate tibiae, and the posterior 

 pair on their basal half, pale yellow or whitish. 



Face wider than in the S > densely punctured, the space between the eyes and 

 mandibles excessively short, so that there are practically no cheeks. Mesothorax 

 dull, densely punctured, anterior area of the propodeum quite diiferent in sculpture 

 to that of the c? , being irregularly or clathrately rugose, posteriorly only forming 

 a very narrow line or groove dividing the posterior elements of the propodeum, 

 which are densely and rugosely punctured and clothed with grey pubescence. Basal 

 segment of the abdomen impunctate, glabrous or nearly so, without lateral spots of 

 pubescence at the apex, the following segments clothed with short grey liairs and 

 very finely punctured. Apical segments clothed above and beneath with dark hairs. 

 Sweeping hairs of the front tarsi well developed. Wings more or less infuscate. 



Length, <? ? , 6-8 mm. 



Explanation of Figures. — Fig. 1, 7th ventral segment of <? ; 2, 8th ventral 

 segment, lateral view ; 3, genital armature of J • 



Sab. : Wicken Fen, Cambridge, and in similar localities in 

 Suffolk, frequenting the flowers of bramble, thistles, &c., and burrowing 

 in the dry stems of the reeds. A common local species, appearing at 

 the end of June in company with P. brevicornis, and later with Ma- 

 cropis labiata at Wicken, all three species being very abundant there, 

 and at the end of July, 1899, these were nearly the only bees to be 

 found in that well known locality. 



Cambridge: January, \200. 



