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



triangular. In male E. abusivus, the yellow patches on tergite 3 were squarish with 

 the vertical inner edge and the bottom edge of the yellow patch forming a 90° angle. 

 In male E. arbustorum the inner edge of the yellow patch on tergite 3, more often 

 than not, curved outwards towards the lateral margins of the tergite. Of course, colour 

 pattern could not always be used. For example, the females of both species are 

 sometimes devoid of all paler pigmentation on the abdomen. However, over 

 of female E. arbustorum were assigned to the categories 3 and 4 shown in Figure 1 

 and over 30% of female E. abusivus were category 3. All of these insects could be 

 instantly identified without reference to further characters. As for the males, over 

 85% of E. abusivus were of category 6 and over 60% of E. arbustorum fell into 

 category 6 or 7. Again, all of these individuals were easy to identify. Clear differences 

 also existed between E. nemorum and the other two species, as can be seen from 

 Figure I, which again facilitate separation of E. abusivus from E. nemorum. 



This study was carried out using insects that were collected in The Netherlands. 

 It is likely, although yet to be established, that the range and type of colour variation 

 shown by E. abusivus in Britain is the same as found in The Netherlands. If this 

 indeed proves to be the case, then colour pattern differences could be a useful way 

 of screening large numbers of Eristalis species quickly and efficiently. 



Acknowledgement 



I am very grateful to Dr Peter van Helsdingen for allowing me access to the 

 Syrphidae collection at the Natuurhistorische Museum in Leiden, The Netherlands. 



References 



Holloway, G. J. 1993. Phenotypic variation in colour pattern and seasonal plasticity in Eristalis 



hoverflies (Diptera: Syrphidae). Ecol. Ent. 18: 209-218. 

 Stubbs, A. E. & Falk, S. J. 1983. British hoverflies: an illustrated identification guide. British 



Entomological and Natural History Society, London, 

 van der Goot, V. S. 1981. De zweefvliegen van NoordwestEuropa en Europees Rusland, in het 



bijzonder van de Benelux. Koninklijke Nederlandse Natuurhistorische Vereneging, Amsterdam. 



ANNOUNCEMENT 



Librarian needed. — I am leaving this position after the 1995 annual general meeting, 

 having performed this function since 1982. Therefore a replacement person is sought 

 for this post as soon as possible. The main duties are to monitor the members' use 

 of the library using computer methods, purchase new material, monitor existing 

 exchanges of journals and arrange new exchanges with other entomological 

 organizations and manage the organization and shelving of the stock. 



The new facilities at Dinton Pastures, combined with the installation of a new 

 computer to use with the society's existing library database make the job o( library 

 management somewhat easier than it used to be at our old rooms in South Audley 

 Street. However attendance is required at the new rooms once a month, as a minimum, 

 to open the post, record and shelve incoming items and monitor loans. 



Due to ever-increasing work commitments and other considerations I feel 1 can 

 no longer give as much time to the position as it requires. A full description ot the 

 duties of the post are available from me, Stephen Miles, Librarian, 469 Staines Road 

 West, Ashford, Middlesex TW15 2AB, tel: 0784 252274. 



