Macromia magnifica
Western River Cruiser is a large, fast, impressive dragonfly that patrols long stretches of rivers that have riffles and ponds. Its discovery in Monterey County in May 2007 was unexpected, as the nearest populations were ~100 miles to the north in the Diablo Range, or ~120 miles to the east in the Sierra Nevada, and represented the southernmost record in the Coast Ranges.

Western River Cruiser is the only member of the family Macromiidae (sometimes considered a subfamily) in California. It is quite large — 3 inches long with a 4 inch wingspan — and thus is larger than all darners, except Giant Darner (which is blue and green, not gray and yellow). The Cruiser resembles only Pacific Spiketail, which also patrols long stretches of rivers or roads and has a black-and-yellow abdomen. The cruiser differs in having a gray thorax with only a single yellow side stripe (the spiketail has two side stripes), gray eyes (not aqua blue), a prominent T-spot on the frons, and a different pattern of yellow spots on the abdomen. Males (above) have 'clubbed' tip of the abdomen and hold their abdomen in a slight arch in flight. When perched (below) the gray eyes meet more broadly atop the head than due the barely-touching eyes of spiketails. Cruisers have very long legs, even as larvae.

All photos 6 May 2007 North fork San Antonio River

Manolis (2003) writes: "Cruisers are named for their fast and powerful flight and the males' habit of patrolling long beats down streams and rivers. Both sexes forage on the wing with great speed and agility, high and low, near and far from water. They are seldom seen perched and are difficult to follow — and even harder to catch."

Hard to catch? Possibly at most places at most times. But when Don Roberson & Paul Johnson found MTY's first cruiser on the San Antonio River, it took Paul only one swing of net the very fearless male that was patrolling low over this shallow pond (below; Paul is removing the dragon from the net in this shot). The in-hand photos on this page are from that capture; more photos about the discovery of this species in MTY and the specific locale are elsewhere on this web site.

When the do perch, cruisers hang vertically from trees or small bushes. When releasing our netted male, we placed it on a perch that it used for a short while (right) until it flew to another (below) for multiple photos. Whether at perch or in flight, this is one very striking dragonfly!

There are 7 species of river cruiser in North America; Western River Cruiser is the only one west of the Rockies. Those in the east can be difficult to identify (e.g., Beaton 2007) and observers focus on whether the yellow ring on segment 2 is broken dorsally (as it is on our ode) and whether the spot atop segment 3 touches the yellow lateral stripe underneath (it does not on our species). We are fortunate that we do not have these tricky identification problems here!

River cruisers are among the fastest fliers of all odonates. Bold and aggressive, they are very impressive in flight. This flight shot (below) was taken by Paul Johnson of MTY's first record.

The map shows the only locale from which Western River Cruiser is currently known in MTY: along the North fork of the San Antonio River near Wagon Caves, Los Padres NF.

In MTY, Western River Cruiser was discovered 6 May 2007 and seen again through 13 May at the San Antonio River site. Elsewhere, flight dates range from mid-April to early September (Manolis 2003).

Literature cited:
  • Beaton, G. 2007. Dragonflies and Damselflies of Georgia and the Southeast. Univ. of Georgia Press, Athens, GA.
  • Manolis, T. 2003. Dragonflies and Damselflies of California. Univ. of Calif. Press, Berkeley.

Web resources:
Major identification web sites with much information on California odes include:

For sites with excellent photos to compare for identification or to simply enjoy, see: Many of these sites have links to other useful pages. Kathy Biggs's site is particularly useful in her selection of links.

All photos © Don Roberson 2007


Page created 14 May 2007