2026 Caterpillar Season – The Slugs

I do not believe I have shared a single slug moth (fam. Limacodidae) caterpillar in 2026. This is mainly because I shared so many of these in the past several years. I did, however, photograph a few this year and I thought I would pool them all in this one post.

First up is the saddleback caterpillar (Acharia stimulea).
The little ones, which are likely 1st instars, were found at Don Robinson State Park in Jefferson County, while the more developed individual was found at the WGNSS trip to Logger’s Lake in Shannon County. Note in the photo on the right that the little ones do not consume the whole leaf, but at this small stage, they scrape the upper layer of the leaf surface.

Next up is the yellow-shouldered slug moth (Lithacodes fasciola).
The healthy final instar individual was found in Ste. Genevieve County in August, while the poor victim of braconid parasitoid wasps was found at Tyson Research Center in early July.

This shagreened slug moth (Apoda biguttata) caterpillar can often be confused with the species before and after. Notice the shagreen-leather-like texture of the integument to discern this one from the yellow-shouldered slug and the following species. This one was found at Don Robinson State Park in mid-September.

The yellow-collared slug moth (Apoda y-inversum) can be identified by the yellow collar at the anterior end along with the yellow sub-dorsal striping. This one was found at Tyson Research Center in early July.

I had a lot of luck finding the crowd-favorite spun glass slug moth (Isochaetes beutenmuelleri) this season. This one was found in Ste Genevieve County in early August on hackberry.

I typically don’t have much luck finding the smaller parasa (Parasa chloris) caterpillars, but this season we discovered five. The two pictured here were found on honey locust and pin oak. Most limacodids are notorious as being highly polyphagous and can be expected on nearly any woody plant species in the state. This year, I found one of this species feeding on the herbaceous wingstem (Verbesina alternifolia).

This beautiful purple-crested slug moth (Adoneta spinuloides) was found at Tyson Research Center in late July.

The spiny oak slug (Euclea delphinii) is typically, but not always found feeding on oaks. This year, however, we found one using Roseshell Azalea (Rhododendron prinophyllum) as host.

Last but not least is this wonderful skiff moth (Prolimacodes badia). These guys come in a wide assortment of patterns, ranging from mostly green, to what you see here, an animal dressed as a scenescent and diseased leaf. This one was found on the WGNSS trip to Logger’s Lake in mid-August.

This covers the slug moth caterpillars I photographed in 2026. One odd thing to note is that no monkey slug cats were found this year. I’m still trying to wrap my ahead around limacodid abundance and dispersal. Some years, certain species are found in large numbers across a variety of habitat types, while the next year they are difficult or impossible to find. These swings are most likely due to parasitoid pressures that wax and wane and are effective biological controls for all lepidopterans.

2026 Caterpillar Season – Verbena Moth

Verbena Moth
Crambodes talidiformis (Guenée, 1852), fam. Noctuidae, P-no. 932030
Host plants: Hosts solely on vervains (Verbena spp.).
Date found(s): September 6, 2026
Location(s) found: Tyson Research Center, St. Louis County, MO
Notes: In the vast world of insects, where single families can contain tens of thousands of species, the verbena moth stands practically alone. It is a monotypic species, meaning the genus Crambodes contains no other living species anywhere else on Earth. Evolutionary biologists find monotypic lineages highly intriguing because they represent isolated branches of the evolutionary tree that have survived without diversifying into a larger cluster of related species.

2026 Caterpillar Season – Bicolored Honey Locust Moth – Redux

I shared photos of this species this year already. However, I was fortunate to find several of these this year and I find these to be one of the more spectacular caterpillars in the state. This one was found in Ste. Genevieve County in early September.

2026 Caterpillar Season – Ragweed Flower Moth

Ragweed Flower Moth
Schinia rivulosa (Guenée, 1852), fam. Noctuidae, P-no. 932091
Host plants: Hosts solely on ragweed (Ambrosia spp.).
Date found(s): September 4, 2026
Location(s) found: Ste. Genevieve County, MO
Notes: For those with a sensitivity to ragweed, like me, the ragweed flower moth should be a favorite. This abundant species feeds on flower buds, blooms and seeds of Ambrosia, acting as a significant natural control for these highly allergenic plants.

2026 Caterpillar Season – False Boneset Flower Moth

False Boneset Flower Moth
Schinia grandimedia (Hardwick, 1996), fam. Noctuidae, P-no. 932095
Host plants: Hosts solely on false boneset (Brickellia eupatorioides).
Date found(s): September 12, 2026
Location(s) found: Don Robinson State Park, Jefferson County, MO
Notes: The false boneset flower moth was described in 1996, most likely due to the similarity of the adult moth to a close relative, the three-lined flower moth (Schinia trifascia). Thankfully, the caterpillars are easily distinguished between the two. Like many of the Schinia, the caterpillars of S. grandimedia feed only on flowers and developing seeds of its host and will almost always be found by looking for them on these tissues.

This species is more common in the great plains and has only a few records from Missouri. This one was found at Don Robinson State Park during a WGNSS caterpillar hunting trip.

2026 Caterpillar Season – Common Buckeye

Common Buckeye
Junonia coenia (Hubner, 1822), fam. Nymphalidae, P-no. 77a0831
Host plants: Hosts include members of the figwort (Scrophulariaceae), plantain (Plantaginaceae), and acanthus (Acanthaceae) families.
Date found(s): August 22, 2026
Location(s) found: Meramec State Park, Franklin County, MO
Notes: The common buckeye’s preferred hosts contain quantities of the bitter and toxic compounds called iridoid glycosides. The caterpillars sequester these compounds and gain considerable protection from them against predators like birds and wasps. However, this protection can come with a considerable tradeoff. High concentrations of iridoid glycosides have been shown to reduce the caterpillar’s immune system, making it incredibly vulnerable to parasitic wasps, flies, and deadly pathogens. To avoid this, female buckeye adults carefully taste potential host plants, striving for just the right amount of iridoid glycosides, prior to choosing the specific plant to oviposit upon.

For the common buckeye, the benefits of this chemical sequestration do not continue to the pupal and adult life stages. Larvae actively metabolize the iridoid glycosides, and these compounds have been shown to drop considerably in late fifth-instar caterpillars and eventually become undetectable in adults. Adults then adopt a different strategy of using warning coloration and patterning of the large “buckeyes” to deter would-be predators.

2026 Caterpillar Season – Silver-spotted Skipper

Silver-spotted Skipper
Epargyreus clarus (Crammer, 1755), fam. Hesperiidae, P-no. 70044
Host plants: Hosts on members of the Fabaceae, including Amporpha, Desmodium, Robinia, and Gleditsia.
Date found(s): September 6, 2026
Location(s) found: Tyson Research Center, St. Louis County, MO
Notes: Here is a lepidopteran even most novice naturalists are familiar with. This is a common and large skipper that is easily identified by the white-silver spots located on the ventral side of the hind wings. This species is often found in backyard gardens and even in urban areas. Caterpillars of this species are best found by looking for leaf tents they build among the foliage of false indigo, wisteria, or other Fabaceae species.

2026 Caterpillar Season – Goatweed Leafwing

I shared photos of caterpillars of the goatweed leafwing last year. Last month, the WGNSS Nature Photography Group went to Don Robinson State Park in Jefferson County, MO for our annual late season caterpillar hunt and found quite a few of these guys on thier croton host plants. I was pleased to get a nice photo of a couple of active late instar larvae pictured here.

And Now for Something COMPLETELY different

I figure any regular viewers of this blog may be getting a little tired of all the caterpillar posts. So, to mix things up a great deal, today’s post is an image of a larval elm sawfly (Cimbex americanus) that I photographed in late May at Tyson Research Center in St. Louis County, MO. Despite looking very much like a caterpillar, I assure you it is not. The sawflies, also known as horntails and wood wasps, are an old lineage (first appearing in fossil records roughly 250 million years ago) within the order Hymenoptera (bees and wasps). The larvae can be distinguished from caterpillars by possessing extra sets of prolegs (six pairs or more). Caterpillars have five or fewer pairs of prolegs. The prolegs of sawflies also lack crochets—the hooklike structures found on the ends of caterpillar prolegs.

The elm sawfly is the largest sawfly in North America. The animal pictured here was very close to two inches long. Accordingly, the elm sawfly adults are large as well, with black, white and red markings making it look very much like an intimidating wasp. No worries there, however, as sawflies do not possess a stinger.

A giant elm sawfly larva. Note the crochetless prolegs. Four pairs of prolegs are visible in this image, but three other pairs can be found in the posterior portion of its body.

2026 Caterpillar Season – Lace-capped Caterpillar

Lace-capped Caterpillar (White-streaked Prominent)
Ianassa lignicolor (Walker, 1855), fam. Notodontidae, P-no. 930106.7
Host plants: Primarily oaks (Quercus spp.).
Date found(s): August 29, 2026
Location(s) found: Tyson Research Center, St. Louis County, MO
Notes: For decades, this moth was known as Oligocentria lignicolor. However, recent genomic research revealed that it was more closely related to the genus Ianassa. This taxonomic revision is a great example of how modern DNA sequencing is proving that species which look similar (like Oligocentria) are not always the closest relatives.