And yet another huge moth


A giant really with a wingspan of 115 mm (~4.5 inches). This is one of the giant silkworm moths known as Antheraea polyphemus. It arrived at my porch light at about 12:30 AM on June 13. So I took a lot of photos then went inside and turned out the light. At dawn it was still there but had fallen from the screen door so I set it on a tarp covered box and placed a small footstool over it for safety. By early afternoon the moth had flown away. I seldom see these large moths, including their larvae, although they are said to be widespread and common. I’m wondering what tonight will bring since I plan on staying up late again.


Antheraea polyphemus silk moths
Antheraea polyphemus showing wing undersides.


A. polyphemus is a distinctive moth species. Apart from its large size the most obvious features are the four eyespots on the wings. There are two small spots on the forewings and two larger ones on the hindwings. The spots on the hindwings are the largest and most brightly colored with a deep black outline surrounding a deep blue interior dusted with many small white specks. at the bottom of the eyespot is an almond-shaped yellow spot with a translucent center. The eyepsots on the upper wings are very much like these yellow spots but with a thin black line enclosing them. The background color of the wings varies individually but is generally a pinkish cinnamon color often dusted with small black specks. Wing margins are separated from the rest of the wing by dark and light-colored bands. The scales on the body, legs, and near the points where the wings attach are long and look like hairs. The moth shown has feathery antennae (used to detect female pheromones) which means it is a male. Females have thinner antennae.

A. polyphemus occurs over most of north America from southern Canada (except Newfoundland) to Mexico and coast to coast in the US.

Larval Hosts
The larvae of A. polyphemus feed on the leaves a variety of deciduous trees and shrubs including oak (Quercus spp.), hickory (Carya spp.), ash (Fraxinus spp.), grape (Vitis spp.), maple (Acer spp.), birch (Betula spp.), pine (Pinus spp.), and willow (Salix spp.).

Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Bombycoidea (Silkworm, Sphinx, and Royal Moths)
Family Saturniidae (Giant Silkworm and Royal Moths)
Subfamily Saturniinae (Silkmoths)
Tribe Saturniini
Genus/species Antheraea polyphemus



Beadle, D. and Leckie, S. (2012). Peterson Field Guide to Moths of Northeastern North America. Houghton Mifflin Harcourt Publishing Company, Boston. 640 pages.

Species Antheraea polyphemus – Polyphemus Moth – Hodges#7757 at the Bug Guide website.

890070.00 – 7757 – Antheraea polyphemus – Polyphemus Moth – (Cramer, 1776) at the Moth Photographers Group website.

I’m tired out

Pachysphinx modesta
Pachysphinx modesta


But it was worth staying up late for the past several nights resulting in the addition of another 25 species to the checklist since June 4. The moth shown above, Pachysphinx modesta, is the latest addition and was made late last night. This is a large moth with a total body length between 45 and 65 mm and a wingspread almost twice that. When it flew by me towards the porch light I thought it was a bird. Pachysphinx modesta occurs over much of North America north of Mexico and can be found wherever the larval host plants poplars and cottonwoods (Populus spp.) and willows (Salix spp.) grow. The related Pachysphinx occidentalis is yellowish brown in the pale form and brownish-gray in the dark form. It can be told apart by the large area of red or pink coloration on the hindwings and by the dark lines that contrast with the background color of the forewings. Pachysphinx modesta is greenish-gray, lines of the forewings do contrast with the background color, and the hindwings are greenish-gray with no red or pink.

Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Bombycoidea (Silkworm, Sphinx, and Royal Moths)
Family Sphingidae (Sphinx Moths)
Subfamily Smerinthinae
Tribe Smerinthini
Genus/species Pachysphinx modesta



Species Pachysphinx modesta – Modest Sphinx – Hodges#7828 at the Bug Guide website.

Species Pachysphinx occidentalis – Western Poplar Sphinx – Hodges#7829 at the Bug Guide website.

A new caddisfly


Nemotaulius hostilis
Nemotaulius hostilis


There are about 277 species of caddisflies in Minnesota but my list of caddisflies from Carlton County is dismally low at only eight species three of which are of uncertain identification plus several unknowns. So when I saw this caddisfly a last week (May 31) I felt pretty sure I had a new species to add to the checklist. And it was. This caddisfly species is Nemotaulius hostilis which in Minnesota is known from several counties in the northern forested region of the state (Houghton 2012).


Class Insecta (Insects)
Order Trichoptera (Caddisflies)
Suborder Integripalpia
Infraorder Plenitentoria
Superfamily Limnephiloidea
Family Limnephilidae (Northern Caddisflies)
Subfamily Limnephilinae
Tribe Limnephilini
Genus/species Nemotaulius hostilis

The larvae of Nemotaulius hostilis build cases from large leaf fragments in such a way that they are sandwiched between the layers (Houghton 2012). This is in contrast to the larval cases of other caddisfly species are tubular or rectangular in cross-section. Larvae live in lakes, marshes, and sluggish streams with thick beds of aquatic macrophytes where they feed on plant debris (Houghton 2012). The small stream that meanders through my property with its abandoned channels and ox-bows contains many sites with dense aquatic vegetation where I hope to find Nemotaulius hostilis larvae later this summer.

The following description of Nemotaulius hostilis is after Schmid (1952), Nimmo (1971), and Houghton (2012). Adult N. hostilis are between 25 and 30 mm long. The coloration and patterning of the forewings is the most conspicuous feature. These are a mixture of solid areas of color, mostly shades of brown, gray-brown, or even black, mixed with clear irrorate (speckled) areas. Schmid says of the translucent speckling (“macules claires”) on the wings that it is “more extensive than in other species” and the wings are “riddled” with them (“l’aile dont toute la surface est criblée de macules claires plus grosses que chez les autres espèces”). The costa is hyaline with some basal irroration. About mid-way on the forewings is a narrow, slanted bright zone. The scalloped wing tips are a distinctive feature.

Nemotaulius hostilis occurs from Newfoundland to Alberta and Alaska, and from New England to the Great Lakes Region, also in Colorado (Nimmo 1971).

Ecological importance
Case-making caddisflies (there are several families) like Nemotaulius hostilis feed by shredding dead leaves and other plant parts that fall into the water or were growing in the water. Some case-making species are predators on small invertebrates while others scrap the fine layer of fungi, diatoms, and bacteria that grow on submerged objects usually wood. A small number of species feed on living plants or construct nets to trap prey or fine particles on which they feed. Shredders and scrappers are especially important in nutrient and energy cycling in forested streams which receive little direct sunlight that would support photosynthetic plants like algae with their ability to produce carbohydrates. In these systems cellulose and lignified woody plant tissue become primary carbohydrate sources which are first acted upon by bacteria and fungi before the insect larvae consume them. Further processing occurs in the gut of the larvae with the help of symbiotic bacteria which reside there. Organisms that feed on caddisfly larvae and adults thus benefit from the ability of the larvae to transform inedible wood and rotting leaves into edible insect bodies. (see Anderson et al. 1978, Wallace 1996, Cummins 2002, Feio et al 2005, Houghton 2007, Resh et al. 2011)

And this one
I found this caddisfly Monday night (June 4). It is one of the giant casemaker caddisflies in the Superfamily Phryganeoidea that is probably Ptilostomis ocellifera, a species which is widespread and common in Minnesota. More on Ptilostomis ocellifera in an upcoming post.


Ptilostomis ocellifera caddisfly trichoptera
Ptilostomis ocellifera



Anderson, N. H, Sedell, J. R., . Roberts, M, and F. J. Triska, J. (1978). The Role of Aquatic Invertebrates in Processing of Wood Debris in Coniferous Forest Streams. The American Midland Naturalist, 100(1):64-82

Cummins, Kenneth W. (2002). Riparian-stream Linkage Paradigm. Verhandlungen des Internationalen Verein Limnologie, 28:49-58.

Feio, Maria J., Vieira-Lanero, Rufino, Ferreira, Veronica , and Graça, Manuel A. S. (2005). The role of the environment in the distribution and composition of Trichoptera assemblages in streams. Archiv fur Hydrobiologie, 164(4):493–512.

Houghton, David C . (2007). The effects of landscape-level disturbance on the composition of Minnesota caddisfly (Insecta: Trichoptera) trophic functional groups: evidence for ecosystem homogenization. Environmental Monitoring and Assessment, 135(1-3):253-64

Houghton, David C . (2012). Biological diversity of the Minnesota caddisflies (Insecta, Trichoptera). ZooKeys 189:1–389. doi: 10.3897/zookeys.189.2043. Description of Nemotaulius hostilis on page 259.

Nimmo, Andrew P. (1971) The Adult Rhyacophilidae and Limnephilidae (Trichoptera) of Alberta and Eastern British Columbia and Their Post-glacial Origin. Quaestiones entomologicae 7:3-234. Description of Nemotaulius hostilis on page 124.

Resh, Vincent H. , Hannaford, Morgan , Jackson, John K. , Lamberti, Gary A., and Mendez, Patina K. (2011). The biology of the limnephilid caddisfly Dicosmoecus gilvipes (Hagen) in Northern California and Oregon (USA) Streams. Zoosymposia, 5:413–419.

Schmid, Fernand. (1952). Les genres Glyphotaelius Steph. et Nemotaulius BKS (Trichop. Limnophil.). Bulletin de la Société Vaudoise des Sciences Naturelles 65(280):231-244. Description of Nemotaulius hostilis on pages 229 to 231.

Wallace, J. Bruce. (1996). The Role of Macroinvertebrates in Stream Ecosystem Function. Annual Review of Entomology, 41:115-139.