Guide to numerical abbreviations for instruments in the orchestra

for example means:

"3 (III – l. fl.)" :

3 flutes; the third flute is a piccolo (little flute) 

for example means:

"4, 4, 5, 4 – 6, 4, 3, 1" :

4 flutes, 4 oboes, 5 clarinets, 4 bassoons – 6 french horns, 4 trumpets, 3 trombones, 1 tuba