[xt600]

Can anyone identify this please? I've found loads of them while digging over my allotment ... 
There are like a transparent sack with orangy/brown gunge at one end.
http://imageshack.us/photo/my-images/7/bugimag0131.jpg/

[ANHBUC]

Is the transparent sack plastic?

[mumofstig]

I did think empty pupal/larval case............but it certainly does look like plastic 

[Mark's Sussex Allotment]

How strange. Rusty nail in a sack lol

[xt600]

No, it's not plastic :-)   If you pick it up it's quite delicate, and certainly not 'empty' or 'used'. It's about the size of a small finger nail.

[snowdrops]

Looks a bit like a tablet say antibiotic. They're not plastic though they look it

[mumofstig]

Empty pupa/larval cases can look like that, perhaps the butterfly/moth (whatever) has died and that explains the mushy brown bit.

A full then empty case shown here, so you can see what I mean

[snowdrops]

Mum that looks fabulous what is it?

[Salmo]

How big are they? Could they have been in compost or farmyard manure that you have spread?

Are there grass snakes locally? If so could they be empty egg cases?

[mumofstig]

Mum that looks fabulous what is it?

I only found it by Googling pupal cases, looking for something to show what I meant - it was from this site near the bottom of the page.

http://bpals.blogspot.co.uk/2008_02_01_archive.html

[xt600]

I'm pretty sure they're not empty cases. There's lots of them, usually a few inches below the surface of the soil. I found some whilst digging last season, but there's many more this time...

[ANHBUC]

Growster managed to get a bug identified recently by contacting
THESE

It might be worth sending them a photo with the information on where found, size etc.