Rationale:

Throws clauses for length_error if n == npos are no longer needed because they are subsumed by the general wording added by the resolution for issue 83.

Proposed resolution:

In [string.require], Strike throws paragraphs for constructors which say "Throws: length_error if n == npos."

The constructor from a range:

template<class InputIterator> 
         basic_string(InputIterator begin, InputIterator end, 
                      const Allocator& a = Allocator());

lacks a throws clause. However, I would expect that it throws according to the other constructors if the numbers of characters in the range equals npos (or exceeds max_size(), see above).