Depressaria ultimella

Foodplant: June and July. Initially in side shoot of Apium nodiflorumwhich it browns, withers and fills with wet orange-brown frass. Later in main stem, where it makes an exit hole plugged with brown silk for emergence of the adult. 

Early instar
Length: 8 mm 
Head: Pitchy black. 
Prothoracic shield: Transparent, tinted yellowish, showing head clearly. Divided by indistinct paler median line. 
Thoracic legs: Shiny transparent yellowish. 
Body: Translucent. Above spiracle level; yellowish, showing viscera indistinctly orange. Whitish yellow below spiracles. 
Spiracles: Black. 
Pinacula: Dark grey with fine black setal spot. 
Setae: Shiny translucent greyish brown. 
Anal plate: Shiny transparent tinted yellowish, showing brown when gut occupied. 
Prolegs: Concolorous.

Intermediate instar:
Length: 12 mm and 16 mm 
Head: Burnt ochre. Capsule and frons thinly edged black. Clypeus and labrum dark brown. Stemmatal area black. Black postero-lateral mark.
Prothoracic shield: Transparent, tinted yellowish and overlaid by faint brown ochre on cuticle. Divided by clear median line showing colour of body or head below. Posterior thinly edged grey-brown. 
Thoracic legs: Shiny transparent yellowish. 
Body: Translucent. Above spiracle level; olive-yellow, showing reddish brown viscera indistinctly. Whitish yellow below spiracles. 
Spiracles: Black.
Pinacula: Dark grey with fine black setal spot. 
Setae: Shiny translucent greyish brown. 
Anal plate: Shiny transparent tinted yellowish, showing brown when gut occupied. 
Prolegs: Concolorous. Crochets reddish brown.

Late instar:

Length: 17 mm 
Head: Raw umber with darker brown dorso-laterally and on frons and mouth parts. Stemmatal area black. Black postero-lateral mark. Posterior of capsule thinly edged black. 
Prothoracic shield: Transparent shiny light brown. Divided by clear median line showing colour of body or head below. Posterior thinly edged darker brown. 
Thoracic legs: Shiny transparent light brown. 
Body: Ventrally, translucent whitish green. Dorsally greyish green with viscera showing as indistinct darker dorsal line. 
Spiracles: Black. 
Pinacula: Dark grey with fine black setal spot.
Setae: Translucent grey. 
Anal plate: Shiny transparent showing green through thinly coloured olive-brown cuticle. 
Prolegs: Concolorous. Crochets reddish brown.