HOVER-FLIES IN ESSEX
81
including S. ribesii, S. corollae, Scaeva pyrastri, S. luniger and S. balteatus,
in that descending order of magnitude. Thompson (1960) exhibited S.
vitripennis and S. ribesii (in a 10:1 ratio) taken from large numbers flying
in a south-westerly direction at Ilford in early August 1960. The year 1960
was clearly a 'good' year for migratory Syrphids, because Chandler (1969)
refers to swarms in other parts of south-east England, and I myself saw
huge numbers of Syrphi at Shoebury East Beach on 6 August: unfortu-
nately I did not collect specimens, but the easily recognizable S. pyrastri
was certainly prominent amongst the swarm.
Arrangement of the List
The sequence and nomenclature of species follows Coe (1953), except
that I have taken account of the recent work of Vockeroth (1969) on the
Syrphini, and of Pedersen (1972) on Paragus and Speight (1973) on
Sphaerophoria. Where this recent work has led to the adoption of names
different from Coe's, I have added the latter in brackets.
The scientific nomenclature and family sequence of wild plants follow
Clapham, Tutin and Warburg (1968); those of garden plants, in so far as
scientific names are used, follow Meikle (1963). Within families, plants are
listed alphabetically. To save space, authors' names of plants are omitted
throughout.
Flight periods of the adult insects are shown only for the commoner
species, for which there are sufficient records to make such data meaning-
ful. These periods, and also the information on associations with plants,
habits, etc., relate only to the county of Essex unless otherwise stated.
1 have prefaced the distribution notes of each species with an indication
of the Watsonian vice-counties in which it has occurred: VC 18 is South
Essex and VC 19 North Essex.
List of Species
Paragus sigillatus Curtis (Paragus tibialis of Coe in part)
VC 18, 19. Waltham Cross, near R. Lea, 21 May 1948 (C. O. Hammond,
det. P. J. Chandler); Linford, a female on flowers of Achillea millefolium
in an overgrown gravel pit, 21 August 1971 (G. Glombek); Leigh-on-Sea,
on flowers of Inula crithmoides, 27 August 1973.
Baccha elongata F.
VC 18, 19. This comparatively uncommon species was included by
Harwood (1903) in his Essex list, though there may have been some con-
fusion with the following species, which does not appear in the list;
however, there are Harwood specimens from Colchester covering the
years 1900-25 in HD. B. S. Harwood's diary for 1905 has an entry
under 25 May: 'Pater and I took 6 Baccha elongata in Nut Hazel Grove.'
This was one of their favourite parts of High Woods. The only recent
specimen is one I took in long grass on Danbury Common on 16 June 1970.
B. obscuripennis Mg. 21 April-20 September
VC 18, 19. A common but rather inconspicuous fly. I have no records
of its feeding at flowers.