Arcigera flower moth (Schinia arcigera) is common and widespread across North America from the east coast to the Rocky Mountains. In Minnesota, it is found from late July to mid-September in fields with asters.
It is active at night and is attracted to light, but can be also found taking nectar on flowers during the day.
This is a small owlet moth. The adult is about ½″ long and has a wingspan of ⅞″ to 1″. It is distinguished from similar moths by dark brown and pale brown coloration, and by a white, smoothly curved, broadly S-shaped postmedial line.
Photo by Bill Reynolds
Sword-bearing conehead (Neoconocephalus ensiger) is a common, large, meadow katydid. It is often heard at night but seldom seen in daylight. During the day it perches head down on the lower stalk of vegetation with only its wings and hind legs visible, appearing like a grass blade. At night the female can be found near a calling male feeding on the seed head of a grass plant.
Sword-bearing conehead has two color phases, leaf green and dark tan. It is most easily identified by the song of the male. The male has sound-producing organs, a “scraper” at the anal edge of the right front wing and a “file” near the base of the left front wing. By rubbing the file against the scraper the male produces a distinctive song. It is a continuous series of high-pitched lisps, clearly separated, produced at the rate of 10 per second. It is often compared to the sound of a distant locomotive.
Aside from its song, sword-bearing conehead is identified by the long wings and antennae; the rounded “cone” at the top of the head that is separated from the head by a gap; the narrow yellowish edging on the thorax and the front wing; and the curved, sword-like ovipositor on the female.
Photo by Bill Reynolds
Masked hunter (Reduvius personatus) is native to Europe and was accidentally introduced into North America. It is now common in eastern and central North America, including Minnesota, but has been reported across the continent.
Masked hunter inhabits woodlands but is often found in human homes. It eats bed bugs and other small insects, spiders, centipedes, and millipedes. It is active at night and hides during the day. If handled or trapped between clothing and skin, it can deliver a painful bite. The swelling and stinging from the bite will last up to a week.
At ⅝″ to ⅞″ in length, masked hunter is much larger than any otherwise similar assassin bugs in North America.
Photo by Bill Reynolds
There are five Zelus species native to North America. Pale green assassin bug (Zelus luridus) is the most common. Due to variation in body color, this species has often been misidentified in the past as Zelus exsanguis. However, that species is very rare. With the exception of a single collected specimen, all sightings of Zelus exsanguis in the United States should probably be recorded as Zelus luridus.
Pale green assassin bug is an elongated, ½″ to 11 ⁄16″ long, nearly parallel-sided true bug. The overall body color is usually pale green, the color of a Granny Smith apple, but may be yellowish-green, yellow, or reddish-brown. Its beak is short and curved. When at rest it is tucked into a groove between the forelegs.
Pale green assassin bug is distinguished by its color; a spine at both rear corners of the pronotum; and a band at the end of the femur that may be dark or red and conspicuous or barely visible.
Oil beetle (Meloe impressus) is an infrequent, medium-sized, blister beetle. Its metallic blue body stands out in sharp relief against green foliage. It lives about one year but has a short season above ground. Adults are active for just two months between August and October. They are found on the ground or on foliage close to the ground. When threatened or mishandled, they exude an oily yellowish liquid that causes blistering on human skin.
Oil beetle larvae pass through four stages and seven molts (instars) before pupating. They live in the nests of solitary, ground-nesting bees, feeding on bee eggs, honey, and stored pollen.
Oil beetles (genus Meloe) are identified by head, body, and legs all metallic blue or black; oval-shaped abdomen; small outer wings (elytra) that overlap at the base and are much shorter than the abdomen; lack of functional inner wings; and antennae that are bent in the middle. This oil beetle (Meloe impressus) is distinguished by the usually brilliant metallic blue, violet, or green, sometimes black coloration; upper margin of the eye that is nearly straight; fifth segment of the antennae enlarged and flared outward; sparse, fine pitting on the head and thorax; thoracic plate with straight sides that converge toward the rear; and a spur on the fourth segment of the hind leg that projects toward the rear.
Lake darner (Aeshna eremita) is the largest mosaic darner (genus Aeshna) in North America. It is a late-season dragonfly, flying to the end of September. It is found throughout Canada, the northern United States, and the Rocky Mountains. In Minnesota it is fairly common in the northern third of the state.
The adult hunts mostly during the day but also sometimes at dusk. It is a strong flier but does not hover during flight. When hunting it cruises above the water surface with its abdomen slightly arched. It often feeds in swarms, sometimes in great numbers, often with other dragonfly species. It often perches vertically on tree trunks, rarely on the ground.
There are at least ten blue darner dragonfly species found in Minnesota and they are notoriously difficult to tell apart in the field. Lake darner is distinguished by its large size, the first lateral thoracic stripe that is deeply notched and has a dot in the notch, and a black line through the upper face.
Toothed somberwing (Euclidia cuspidea) is common and widespread across North America from the east coast to the Rocky Mountains. In Minnesota, it is found from mid-May to early July in meadows and in woodland edges and openings with long grass.
It is active both day and night. When flushed from vegetation it flies rapidly for about 20 yards then drops to the ground. It rests with the wings held flat and the hindwings usually concealed. It is attracted to light.
This is a stout, medium-sized moth. The adult is about ⅞″ long and has a wingspan of 1⅛″ to 17 ⁄16″. It is distinguished from similar moths by dark brown triangular spots on the forewing of the adult, and by the presence of reduced leg-like structures on the fourth abdominal segment of the caterpillar.
Japanese beetle (Popillia japonica), native to northern Japan, was first found near Riverton, New Jersey in 1916. Two years later attempts to eradicate it by the USDA failed. It had become established — the population was too large for attempts to control it to be successful. It is now widespread across North America, reported in all of the contiguous 48 states except for Florida. It is well established from Maine to Minnesota south to Arkansas and Georgia.
Japanese beetle is a destructive pest in North America where it has no natural enemies. The larvae feed on roots of grass and other plants, causing damage to lawns, parks, golf courses, and pastures. Adults feed on leaves, flowers, and fruits of several hundred species of plants, including fruit trees, ornamental trees, shrubs, vines, field crops, and vegetable crops. They skeletonize leaves by eating the soft tissue but leaving the larger veins. They have caused 50% to 90% defoliation of birch and cottonwood trees in some neighborhoods of the Twin Cities.
Japanese beetle is a colorful, medium-sized, scarab beetle. It is identified by a metallic green head and thorax, iridescent. bronze or coppery wing covers, and white tufts of hairs at the sides and end of the abdomen.
Many insects form detachable galls on oak. All but two of these are cynipid wasps. The two exceptions are the oak gall midges Polystepha pilulae and Polystepha globosa.
Oak leaf gall midge (Polystepha pilulae) is a long-legged, 1 ⁄16″ to ⅛″ long, mosquito-like fly (midge). Adults are impossible to identify by appearance in the field. However, the species can easily be identified by the gall it produces. Galls appear always on the upper surface of northern pin oak, northern red oak, and possibly black oak leaves. They are hard, 1 ⁄16″ to 3 ⁄16″ in diameter, and irregular in shape. They are green when they first appear in the spring, soon turning red or magenta. As they age they become brown and crusty. They can be easily detached from the leaf surface.
Oak leaf gall midge (Polystepha globosa) forms similar spherical galls on the undersurface of the leaves of black oak and possibly other oaks in the red oak group.
Grape phylloxera (Daktulosphaira vitifoliae) is a very small, soft-bodied, aphid-like insect. It has a complex life cycle with up to eighteen stages and four distinct forms.
Grape phylloxera is a pest of grapevines around the world. It originated in southeastern United States, where some American grape species developed resistance or tolerance to it. It was introduced into France in 1860 when infected vines were imported for their resistance to powdery mildew. In the next 40 years the pest destroyed nearly two-thirds of wine grape vineyards in Europe.
Grape phylloxera adults are difficult to identify because of their extremely small size. They are usually identified by the galls they produce on the roots and leaves of grape plants. Galls on the tips of rootlets are yellowish-brown, hook-shaped swellings. Galls on larger roots are rounded, wart-like swellings. Galls on the underside of leaves are small, green, rough, and more or less globular.