Are you looking for specimens? We capture G. materiarius all the time when we trap throughout the northeastern United States (New Hampshire, Maine, New York, Massachusetts mostly). I'm happy to help get you specimens if needed, or I can provide coordinates of places where we have captured G. materiarius before.
thank you for your answer. I have specimens but I want to compare some climatic conditions in places of occurring of G. materiarius. I found more than 500 localisations so I do not need more. Thank you for your offer. If you need sth from Poland and I have it I can send it, or we can make exchange.