Key to the species of Choristoneura from China

1. Forewing without conspicuous pattern............................................................. 2

- Forewing with conspicuous pattern............................................................... 3

2. Uncus with distal half conspicuously expanded, rounded apically....................... C. expansiva sp. nov.

- Uncus slender, without distal expansion........................................ C. luticostana (Christoph)

3. Male forewing without costal fold................................................................ 4

- Male forewing with costal fold................................................................... 7

4. Forewing pattern distinct....................................................................... 5

- Forewing pattern indistinct..................................................................... 6

5. Forewing scattered with short strigulae; uncus with distinctly expanded part.............. C. diversana (Hübner)

- Forewing with few short strigulae; uncus without expanded part....................... C. murinana (Hübner)

6. Forewing whitish gray; uncus short; socius small; transtilla narrow; sacculus with prominence ventrally; aedeagus with a ventral acute dent apically............................................... C. thyrsifera Razowski

- Forewing brown; uncus slender; socius large; transtilla broad; sacculus smooth ventrally; aedeagus with some small dentate apically............................................................. C. metasequoiacola Liu

7. Male forewing with short costal fold, not exceeding middle of costa.................... C. evanidana (Kennel)

- Male forewing with long costal fold, exceeding middle of costa......................................... 8

8. Costal fold of male forewing broad and from basal 1/5 to 2/3 of wing; forewing with a large black blotch near base; sacculus with a dorsal dent at middle....................................... C. longicellana (Walsingham)

- Costal fold of male forewing narrow and from base; forewing without blotch near base; sacculus smooth dorsally 9

9. Sacculus with large horned process ventrally; aedeagus pointed apically............... C. lafauryana (Ragonot)

- Sacculus narrow and smooth ventrally; aedeagus with a small dent apically.................................................................................................... C. adumbratana (Walsingham)