UK I INI NAI HIST., 1.1: 2001 193 



RHYZOBIUS CHRYSOMliLOlDliS (HERBST) (COLEOP1 EH \: 

 COCCINELLIDAE) NEW TO BRITAIN 



Roger D. Hawkins 



30D, Meadnurio/i Close. Horley, Surrey RH6 9EL 



Abstract. The small European coceincllid beetle Rhyzobius chrysomeloides (Herbst), 



not previously known in Britain, has been found in Surrey (VC 17) at two localities. 

 Comparison is made with the common British species Rhyzobius litura (Fah.i. 



Introduction 



The banks of motorways are often considered to be the equivalent of a nature 

 reserve but few people have either the opportunity or the inclination to examine their 

 flora and fauna since they are subject to extremes of noise and pollution, while 

 unauthorised access is officially discouraged. An exception to this occurs near the 

 village of Nutfield in east Surrey where the M23 motorway bursts through the 

 Greensand ridge in a deep cutting and crosses the valley to the north on an 

 embankment before ascending the chalk hills of the North Downs. There is a solid 

 fence at the top of this embankment, probably to contain the noise of traffic, so 

 access to the slopes is possible. 



About one kilometre to the north-east of Nutfield, at grid reference TQ312516, a 

 track passes under the motorway to connect Lake Farm on the east side with some 

 cottages and fields to the west. This track is also a public footpath and on 26. iv. 1996 

 I came along this path while routinely recording ladybirds (Coccinellidae) and other 

 insects for a series of local atlases. A group of young pine trees (Pimis sylvestris L.) 

 had been planted on the west bank of the motorway and were then about four metres 

 high. From one of these pines I beat a small orange-brown coccinellid which I 

 assumed to be Scymnus suturalis Thunberg, a species found commonly on pine. As is 

 advisable with these tiny beetles, I took the specimen home for checking but. on 

 mounting it, I realised that it was a larger insect than the Scymnus. with longer 

 antennae, and was clearly a specimen of Rhyzobius. 



About a year later I tried to name the specimen using the key by Fursch (1967) to 

 the Coccinellidae of central Europe. It appeared to be Rhyzobius chrysomeloides 

 (Herbst), a widespread species on the European mainland that had not previously 

 been recorded from the British Isles. The external differences between this species 

 and our common R. litura (Fab.) are slight and it is advisable to check the male 

 genitalia. At that time I had no experience of dissecting such a tiny beetle and a 

 tentative probe produced only a minute piece of gut which caused me to think it was 

 a female. The specimen was then taken to Dr R. G. Booth who pronounced that it 

 was in fact a male, dissected it immediately and confirmed that it was indeed 

 R. chrysomeloides. 



Comparison with rhyzobius litl ra 



The differences between these two species are illustrated by Fursch (1967). The 

 sides of the pronotum of litura taper from the base, and increasingly towards the 

 front, while the pronotal edges of chrysomeloides are almost parallel-sided over 

 the basal quarter (Fig. 1). The prosternal carinae (between the fore coxae) of 

 litura taper gradually from rear to front, while in chrysomeloides the tapering is 

 interrupted by a parallel-sided central section and the apex is broader (Fig. 2). 



