Three insects added to my checklist this morning

Big-leaf aster (Eurybia macrophylla) in bloom out in the woods.

It is the first day of October, but it doesn’t feel like it. Our temperatures are in the high 70s, and the warm weather will continue at least until Sunday. So I decided to look for any flowers that might still be blooming on this unseasonably warm autumn day. Although there is not a profusion of flowers this far into autumn, some still can be found.

Two that are still in full bloom are showy goldenrod (Solidago speciosa) and trumpet weed (Eupatorium fistulosa). These two plants are always pollinator magnets, and today they were loaded with bumblebees, syrphid flies, and wasps.

While taking photos, I saw three insects that I had not recorded from here before: Pararchytas decisus (a tachinid fly), Sericomyia militaris (a syrphid fly), and Eumenes crucifera (a potter wasp).

Pararchytas decisus
Sericomyia militaris
Eumenes crucifera

Warm autumn days like this one never fail to surprise. I wonder what I will find later today and tomorrow?

Halysidota tessellaris (Banded Tussock Moth): Identification and Life Cycle

In an earlier post, I wrote about Lophocampa maculata, a moth in the Arctiinae, distinguished by its fuzzy black and yellow larvae. These larvae later metamorphose into beautiful adult moths with a contrasting pattern of alternating bands of warm, muted golden-orange and darker brown markings with a reddish-orange tinge. In this post, I write about Halysidota tessellaris, the banded tussock moth, another moth in the Arctiinae.

Halysidota tessellaris caterpillar feeding on a crabapple leaf in late summer.

Identification

Like Lophocampa maculata, the larvae of Halysidota tessellaris are also fuzzy, but they are usually gray to dingy brown with long white and long black tassels. The adult moth, while similar in size to Lophocampa maculata, has translucent yellow forewings marked with slightly darker bands and irregularly shaped block-like cells that form a tessellated pattern. Also, there are two parallel blue stripes on the fuzzy thorax.

Life cycle

Across its range, larvae of Halysidota tessellaris feed on many species of hardwood tree leaves. Among these are box elder (Acer negundo), sweet birch (Betula lenta), ash (Fraxinus spp.), oaks (Quercus spp.), and many others. Adult moths take nectar and are pollinators of milkweeds (Frost, S. W. (1965) Insects and Pollinia. Ecology, 46. 556-558, paywall).

Halysidota tessellaris, a worn specimen, but the blue lines are prominent.
Halysidota tessellaris showing the tessellated pattern of the forewings.

Similar species

Adults of the related Halysidota harrisii (sycamore tussock moth) are similar in appearance to Halysidota tessellaris. Where the ranges of Halysidota tessellaris and Halysidota harrisii overlap, genital dissection is necessary to determine the species. Halysidota harrisii larvae, which may be solid white, yellow, orange, or gray, feed exclusively on sycamore (Platanus occidentalis) leaves. The ranges of sycamore and the moth coincide closely.