NYBG has at lest parts of its herbarium collection online at:
(try searching for family nepenthaceaea)
Most impressive are the high quality scans of the sheets when taking into mind that taxonomists do have to work with this material! Some sheets are even without a single pitcher...
Easy to recognize Isotype of N. campanulata:
(in big: http://image.nybg.org/herbim/1300/v-130-00039332big.jpg )