70.267 Hypomecis roboraria (Great Oak Beauty)
fw: 21-32mm; Jun-Jul; pedunculate oak (Quercus robur); NS-B in large mature oak woodlands in SC.England especially Hampshire, Sussex, Surrey & Berkshire
Hypomecis roboraria (Great Oak Beauty) §1 male
ID: Distinguished from similar species by size; convergence of 2nd & 3rd cross-lines to form a dark blotch at the dorsum; small dark central spot on hindwing. Most similar to H.punctinalis (Pale Oak Beauty) in which 2nd and 3rd cross-lines converge to a lesser extent and do not form a dorsal blotch and the hindwing spot has a pale centre.
I have never encountered a specimen with a size in the overlap range between Willow Beauty and Great Oak Beauty, but such a specimen may be problematic to identify if obtained in ancient oak woodlands. In specimens I have examined the central hindwing spot in Great Oak Beauty is midway between the median and antemedian lines or slightly closer to the antemedian line; in Willow Beauty this spot, when discernable, is clearly closer to the median line.
I have never encountered a specimen with a size in the overlap range between Willow Beauty and Great Oak Beauty, but such a specimen may be problematic to identify if obtained in ancient oak woodlands. In specimens I have examined the central hindwing spot in Great Oak Beauty is midway between the median and antemedian lines or slightly closer to the antemedian line; in Willow Beauty this spot, when discernable, is clearly closer to the median line.
Dissection
Male genitalia
§1 New Forest, Hampshire; 27/06/2008; male
§2 New Forest, Hampshire; 27/06/2009; male
§3 New Forest, Hampshire; 29/06/2009; male
§4 New Forest, Hampshire; 20/06/2016; male
§5 New Forest, Hampshire; 20/06/2016; male; fw 28.2mm
§6 New Forest, Hampshire; 20/06/2016; male; fw 25.3mm
§7 New Forest, Hampshire; 22/06/2016; male
All images © Chris Lewis
§2 New Forest, Hampshire; 27/06/2009; male
§3 New Forest, Hampshire; 29/06/2009; male
§4 New Forest, Hampshire; 20/06/2016; male
§5 New Forest, Hampshire; 20/06/2016; male; fw 28.2mm
§6 New Forest, Hampshire; 20/06/2016; male; fw 25.3mm
§7 New Forest, Hampshire; 22/06/2016; male
All images © Chris Lewis
Page published 06/03/2014 (§1-3) | §4-7 added 29/05/2017
