1883.] 87 



(B. cognatus, Steph., := venustus, Sm.) is not generally an abundant species, but on 

 the Teucrium on the eastern front of the Island, it is common enough, but apparently 

 local, as it hardly extends over an area of more than half a mile, and seems only to 

 occur on the coast; our other usually very common s-^ec\es,\'\z.,hortorum,terrestris, 

 and muscorum, are distinctly rare, muscorum apparently taking the place of cognatus 

 inland. Although these two species are so much alike when examined at home, yet 

 on the wing they can be known at once by their general appearance, the black hairs 

 of the legs and the sides of the abdomen of muscorum, and the deeper brighter 

 orange band of the 2nd abdominal segment in cognatus, shewing as distinct charac- 

 teristics. 



Of the parasitic genus Psithyrus I have found four out of our five British species, 

 but only one or two of each, and all males. Prosopis dilatata, once looked upon as 

 such a great rarity, may be taken freely, especially in the female sex, and frequents 

 a curious variety of flowers. I have taken it on Euphorhia segetalis abundantly, 

 on Achillea millefolium abundantly, on Echium vulgare frequently, and on small 

 yellow CompositcB such as Leontodon hirtus, Crepis virens, &c., occasionally. It is 

 hard to fancy a selection of plants less alike than those given above, difPering widely 

 in colour, and belonging to three distinct natural Orders, — Achillea, moreover, being 

 distinct from the other Composite which the bee frequents in its strong aromatic smell. 

 Five of the other British species have been found in the Island, nearly all fi'equenting 

 the bramble-flowers along the coast. 



In the genus Halicttis, sixteen of our British species have appeared, and amongst 

 them two of our rarest, viz., H. hrevicornis, Schenck, and H. breviceps, E. S. Of 

 the genus Pompilus, I have found six species, two of which are rarities, viz., ungui- 

 ctdaris and consobrinus ; unguicularis occurring only on the sand hills on the east 

 of the Island, consobrinus only on those of the west ; the common plumbeus occurs 

 on both and in great numbers ; of rufipes, I have found a very few on thistles to the 



east, and of viaticus, usually so common, I have only found two females. Only one 



ant of any rarity has occurred to me, viz., Leptothorax unifasciata, of which I found 



a colony under a stone on the green towards the west, it contained about seven 



females, at least I was able to capture that number, but others might have escaped 



among the stones, and about thirty or more workers, and a good many larvae. The 



following is the list of my better captures : — 



Leptothorax unifasciata, Latr., under a stone. 



Mutilla ephippium, Fab., on the sandhills to the east of the Island. 



Pompilus rufipes, Lin., on thistle heads. 



„ consobrinus, Dahlb., on sandhills west of the Island. 

 „ unguicularis. Thorns., on sandhills east of the Island. 



Ammophila lutaria, Fab., on sandhills east of the Island. 



Nysson diviidiatits, Jur., a single specimen on a bank. 



Vespa sylvestris. Scop., frequent on Scrophularia. I have taken it on the same 

 plant at Chobham. 



Odynerus 3-marginatus, Zett., frequent on thistle-heads. 



Prosopis dilatata, Kirb., on various flowers. 

 „ confiisa, Nyl., on Rubus. 



Halictus zonulus, Sm., $ , on Centaurea. 



„ brevicornis, Schenck, S , on thistle-heads, very local. 



