62 BR. J. ENT. NAT. HIST., 7: 1994 



On 10.vii.1965, 1. H. H . Yarrow discovered the species in a second site on Salisbury 

 Plain (Yarrow, 1968). Shortly before he emigrated to Australia in the 1980s, he 

 disclosed to G. R. E. that the site was a neolithic barrow south-west of Tilshead (near 

 Horse Down, north of the Chitterne road), not far from Currie's site. 



In 1991 we rediscovered the bee near White Barrow on 16.vii, and on the following 

 day at both Yarrow's site and West Down (east of and overlooking the army camp). 

 In addition we also encountered it in two new sites: about a kilometre north of Tilshead 

 and on the roadside about a kilometre east of West Down. It was particularly 

 common at West Down, but only occurred in small numbers in the other sites visited. 

 S. R. Miles (pers. comm.) found the bee at West Down in both July 1986 and 

 July 1991. 



In the following year we again found it on several dates in late June and July to 

 the north of Tilshead and at West Down. Seven females and at least 36 males were 

 seen by us on West Down on 27. vi, and both sexes plentifully on 28. vi by S. P. M. R. 

 (from the roadside, south across the army range towards the main Tilshead to Shrewton 

 road). 



A further three sites for the species were found in 1993: Great Cheverell Hill (l.vii 

 and on subsequent visits in the same month); Figheldean Down (in late June by 

 D. Sheppard, and later by the authors on 1 l.vii and on a few visits thereafter). 

 R. Gabriel encountered several males at a site 1 kilometre north-west of Tilshead 

 on the West Lavington Road (east of Horse Down) on 16.vii. 



The bee is protandrous, the males emerging ahead of the females. The former 

 begin flying in late June and continue well into July. When freshly emerged, males 

 are clothed over much of their bodies with rich, reddish brown hairs, but this colour 

 rapidly fades to whitish, when specimens appear silvery on the wing. 



Males fly rapidly between the sainfoin plants, only pausing occasionally for brief 

 visits to the flowers. During cool, cloudy conditions this sex has been observed 

 sheltering within the racemes of sainfoin and in the flowers of clustered bellflower 

 (Campanula glomerata L.), field scabious and oxeye daisy. Females are generally active 

 from late June to mid August (in 1993 an apparently freshly emerged specimen was 

 found on 3 l.vii). In common with the other three species of British Melitta, they 

 are not as frequently seen in the field as males. The females excavate their nesting 

 burrows in the soil, but no nests of this bee have been found in Britain. 



In Britain both sexes are known to forage only from the flowers of sainfoin. Thus 

 M. dimidiata is entirely restricted to sites where there is sufficient sainfoin to maintain 

 these populations. This plant is very widely distributed over the semi-natural 

 grasslands of Salisbury Plain, with significant populations in many sites. Indeed, as 

 a single unit, the Plain probably has the most extensive populations of this plant in 

 the country. 



Two forms of sainfoin occur in southern England, one native, the other introduced. 

 The native one (ssp. montana Hegi) is characterized by deep pink flowers and fewer 

 leaves, and is semi-procumbent to erect in form (Hegi, 1924; Dony 1953; Grose, 1957). 

 There are late glacial British pollen records of sainfoin (Godwin, 1975), and it is 

 presumed that M. dimidiata subsequently arrived in Britain in boreal or sub-boreal 

 times (Baker, 1965). In addition, there are records of sainfoin in the writings of Gerarde 

 (1597), Goodyer (c. 1634), Martyn (1792) and Britton (1801-25). Gerarde noted it 

 in areas which today support strong populations of ssp. montana. 



During the seventeenth century, another variant (ssp. sativa Hegi) was introduced 

 as a fodder plant (Aubrey, 1685). This taxon differs from the native form in being 

 taller, more erect, and the stems bearing paler flowers and more leaves, with broader 

 leaflets, than its relative (Hegi, 1924). This introduction is now found as a relic 



