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Hello,

When setting up the patio furniture for the spring, we discovered this pupa on one of the chair legs. I’m sure it is either Small or Large White but cannot convince myself which one. Some confirmation would be appreciated
Kind Regards Kev

Hi Kev,

For my money, that's a Small White.

The colouration looks best for Small White, although there is a lot of variation within the species and closely related ones.
As far as diagnostic features are concerned, I tend to rely on the size and shape of the dorsal ridge, near the head.
In the Green-veined White, it's usually quite tall, with a convex curve as it slopes down towards the tail end. The Large White tends to have a shorter dorsal ridge (compared to the rest of the pupa) and then a small, but noticeable secondary ridge, just below. The Small White usually has a tall dorsal ridge with a concave or straight return towards the tail end. Another point is that a Large White pupa is approximately 25mm long, whereas a Small White is only around 19mm.
Annoyingly, some pupae do not follow all of the rules, and yours has a slightly convex return on the dorsal ridge, but I have already ruled out Green-veined White in this case. If it's still viable, it should be colouring-up soon, so the question should be solved once and for all.

Vince

Vince,
Thanks for the informative reply and comparison photos.

Kind Regards
Kev