Arthropods of Eaton Canyon

Bee Fly (Anthrax albofasciatus cascadensis); Family: Bee Flies (Bombyliidae); Order: True Flies (Diptera)

Bee flies get their name from their nectar-feeding habit, as well as their furry appearance. As nectar-drinking insects, they may also pollinate the flowers they visit. The larvae of bee flies are parasitic on burrowing and hole-nesting insects, such as solitary bees. The fly pictured here was found on a log in Moist Canyon, a tributary wash of lower Eaton Canyon.

The San Gabriel Mountains are about the southernmost reported area for this species, according to entomologist Neal Evenhuis of the Bishop Museum in Honolulu, HI. Evenhuis, who identified this species, is an authority on bee flies.

Bee Fly

Photo by Hartmut Wisch

Note the furry appearance.

Box Elder Bug (Boisea rubrolineata); Family: Scentless Plant Bugs (Rhopalidae); Length: ~ 1/2 inch (13 mm)

Though superficially similar to the Small Milkweed Bug (Lygaeus kalmii), the Box-Elder Bug is distinguished by a bright red abdomen, orange to reddish wing margins, and red eyes. This bug feeds primarily on broad-leaf trees, such as box-elder, ash, maple, and sycamore. Seen especially on warm spring days. The accompanying photos show a Box-Elder Bug nymph on leaf litter and an adult on a young sycamore (Platanus racemosa) leaf.

Box Elder

Photo by Hartmut Wisch

Note the orange - to reddish wing margins and red eyes.

Brown Leatherwing (Cantharis consors); Family: Soldier Beetles (Cantharidae)

Adults are about 5/8 to 3/4 inch long. Though little is known about the habits of this beetle, adults feed on Aphids and other insects. If handled, these insects may give off an unpleasant odor.

Brown Leatherwing

Photo by Hartmut Wisch

The specimen seen here is on a Mugwort (Artemisia douglasiana) leaf.

Honeybee (Apis mellifera); This is the European honeybee, not our native species.


Photo by Bruce Marschall (2005)

This honeybee is moving to a new Bermuda buttercup blossom (Oxalis pes-caprae). Notice the already bulky load of orange pollen attached to his legs.

Tachinid Fly (species not identified); Family: Tachinid Flies (Tachinidae); Order: True Flies (Diptera)

Adults feed on nectar. The females deposit their eggs on insects and other arthropods. Their larvae subsequently become internal parasites, eventually killing their host. The tachinid in the photo is seen on a flower head of Long-Stemmed Buckwheat.

Brian Brown, Associate Curator of Entomology, Natural History Museum of L.A., confirmed the ID.

Tachinid Fly

Photo by Hartmut Wisch

Seen here on Long-stemmed Buckwheat (Eriogonum elongatumvar. elongatum)

Tarantula (genus Aphonopelmus)


Photo by by Gabi McLean ©1998

This specimen was photographed by Gabi McLean in Fish Canyon

Characteristics of All Arthropods

Arthro- "joint";  Pod- "leg"

  1. They are invertebrates with an exoskeleton, or protective covering, comprised primarily of chitin.
  2. They have true appendages.
  3. They have highly-developed sense organs.
  4. They have highly-developed nervous systems.