. British journal of entomology and natural history. Natural history; Entomology. 124 BR. J. ENT. NAT. HIST., 4: 1991 traps (white plastic bowls 20 cm in diameter and 9 cm deep). Both the pitfall and water traps were partially filled with a mixture of 10% ethylene glycol in water and were emptied every 2 weeks during two trapping periods; 23 May to 5 July and 29 August to 27 September. The locations of these traps are described in Morris & Parsons (1991a). During the survey in 1988, parasitic Hymenoptera were not a target group and only a limited sample of material was retained. As a resul
. British journal of entomology and natural history. Natural history; Entomology. 124 BR. J. ENT. NAT. HIST., 4: 1991 traps (white plastic bowls 20 cm in diameter and 9 cm deep). Both the pitfall and water traps were partially filled with a mixture of 10% ethylene glycol in water and were emptied every 2 weeks during two trapping periods; 23 May to 5 July and 29 August to 27 September. The locations of these traps are described in Morris & Parsons (1991a). During the survey in 1988, parasitic Hymenoptera were not a target group and only a limited sample of material was retained. As a result, data for this period is only available from trapping in August and September. In 1989, an interest in a small group of parasitic Hymenoptera led to recording of Chalcididae. For the purposes of this article, the comments are therefore confined to the results of work in 1989 when it was possible to extract all relevant material. In 1989, a total of 380 individuals of/, subarmata were recorded. Figure 1 shows the numbers captured in each trapping period and from the available data, the peak frequency of /. subarmata appears to be August but, as there was a gap between trapping periods, this is not certain. There is a distinct succession of vegetation types at Dungeness which is described by Ferry and Barlow (in Ferry & Walters 1985). Further studies and a classification of shingle vegetation are described by Ferry et al. (1990) and, as a result of this work, the vegetation is mapped by Fuller (1989). The trapping stations were arranged so that they remained within a distinct vegetation type and therefore, it is possible to compare the results of pitfall and water trapping against vegetation type (see Ferry et al., 1990, page 94). Comparing the average number of individuals per trap run. Key to Vegetation Types 1 Crambe 2 Arrhenatherum B3 3 Acid heath A1 4 Acid heath A2 5 Acid heath A2S 6 Acid heath A2f 7 Acid heath A3 8 Mesotrophic B1 9 Wetland B2 Wetland with Salix B2S Ba
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