Species Phereoeca uterella - Household Casebearer - Hodges#0390

0390

formerly Plaster Bagworm

formerly P. walsinghami and dubitatrix

the only species in this genus in North America

adult male wingspan 7-9 mm; female wingspan 10-13 mm

fully-developed larva about 7 mm; larval case 8-14 mm

Adult: forewing gray with up to four spots and a brush of long, lighter gray hair-like scales along inner margin of hindwing; males are smaller, thinner, and have a less distinctive wing pattern than females

Larva: larval case is slender, flat, fusiform, or spindle-shaped, resembling the seed of a cantaloupe or pumpkin

southern United States

Larval cases can be found on wool rugs and wool carpets, hanging on curtains, or under buildings, hanging from subflooring, joists, sills and foundations; also found on exterior of buildings in shaded places, under farm sheds, under lawn furniture, on stored farm machinery, and on tree trunks

larvae feed on old spider webs; may also eat woolen goods of all kinds if the opportunity arises

The larval case is silk-lined inside and open at both ends. The case is constructed by the earliest larval stage (1st instar) before it hatches, and is enlarged by each successive instar. In constructing the case, the larva secretes silk to build an arch attached at both ends to the substrate. Very small particles of sand, soil, iron rust, insect droppings, arthropod remains, hairs and other fibers are added on the outside. The inside of the arch is lined exclusively by silk, and is gradually extended to form a tunnel, while the larva stays inside. The tunnel is closed beneath by the larva to form a tube free from the substrate, and open at both ends. After the first case is completed, the larva starts moving around, pulling its case behind. With each molt, the larva enlarges its case. Later cases are flattened and widest in the middle, allowing the larva to turn around inside.

[from Featured Creatures, U. of Florida]

comprehensive illustrated article on all aspects of the species (Featured Creatures, U. of Florida)

live larva and case image plus description, food items, and other info (Common Insects of Los Angeles Basin, Natural History Museum of Los Angeles County)