The text on page 32 of the Basic Rules that talks about copying spells does not explicitly state that the process consumes the scroll. Does it?
The DMG states:
Whether the check succeeds or fails, the spell scroll is destroyed. (DMG 200)
I tweeted the question to Mike Mearls, and he confirmed that as far as he knows spell scrolls are in fact consumed during the copying process. I will consider this to be the case until future published materials contradict Mike's assertion. Tweets provided below.
@mikemearls Does copying a spell scroll into a Wizard's spellbook consume the scroll? The basic rules don't seem to explicitly say so.— Matthew Boyette (@Dyndrilliac) August 2, 2014
@Dyndrilliac believe it does— Mike Mearls (@mikemearls) August 2, 2014
This is now specifically addressed in the DM's Guide, in the list of Magic Item descriptions. On page 200 is the entry "Spell Scroll", which concludes with the steps necessary to copy a scroll, including the final sentence:
Whether the check succeeds or fails, the spell scroll is destroyed.
Way back in ye olde days (1980 or thereabouts), the first edition DMG answered thus:
Use of Spell Scrolls: When any scroll is read for purposes of copying the spell's formula (so as to be able to "know" it) or to release its magic, the writing completely and permanently disappears from the scroll. The magic content of the spell is bound up in the writing, and use releases and erases it. Thus, reading a spell from a scroll of 7 spells makes the thing a scroll of 6 spells. No matter what a player may attempt, a scroll spell is usable but once and once only. No exceptions should be made save in the case where you have a special magic item in mind - perhaps a scroll which can be read from once per week or whatever - and always only in rare finds. (DMG 1st ed., p. 128)
Now I realize that many things have changed since such ancient times - including the number of younglings hanging about on my lawn - the logic does still seem sound.