Powder Valley Conservation Area – A Thousand Acres of Silphiums

2026 Caterpillar Season – Elm Sphinx

2026 Caterpillar Season, Caterpillars of Tyson Research Center, insects, Lepidoptera, macro, WGNSS Field Trips, wildlife, wildlife photography

Elm Sphinx (Four-horned Sphinx)
Ceratomia amyntor (Geyer, 1835) P-no. 890102
Host plant: Found on American elm (Ulmus americana)
Date found(s): July–August, 2026
Location(s) found: Carter County, MO, Ste. Genevieve County, MO; St. Louis County, MO
Notes: An excellent example of camouflage. The four thoracic horns aptly mimic the teeth on the margins of the leaves on which they feed. These larva spend most of their time hiding upside-down on the undersides of elm leaves. The pale, oblique lines leading from the stomata to the mid-dorsal line let them blend in with elm leaves that feature prominent pinnate venation on their undersides (see photo).

2026 Caterpillar Season – Byssus Skipper

2026 Caterpillar Season, insects, Lepidoptera, macro, WGNSS Field Trips, wildlife, wildlife photography

Byssus Skipper
Problema byssus (Edwards, 1880) P-no. 77a0186, fam. Hesperiidae
Host plant(s): Found on eastern gamagrass (Tripsacum dactyloides)
Date(s) found: 18 July, 2026
Locations found: Powder Valley Conservation Area, St. Louis County, MO
Notes: My first grass skipper cat! Byssus skipper caterpillars spend their time in cylindrical shelters typically made from one grass stem. Look for these in higher quality prairie habitats where their host plants are abundant. Due to loss and degradation of grassland habitat, the byssus skipper and most of the grass skippers are at risk. Although the byssus skipper has a wide range, it is not considered common in any state.