Calvert County (MD) Dragonflies and Damselflies: Part Eight – Dragonfly Family Macromiidae

Family: Macromiidae (Cruisers)

There are only four known species of this family in the official Maryland state record. Only two of the four species are listed for southern Maryland and only one of those for Calvert County. Within the iNaturalist database, observations for species within this family are quite sparse for the entirety of Maryland. There are currently no observations recorded in iNaturalist for this family of dragonflies in the three southern Maryland counties.

Listed below are the two species within the Macromiidae family that have been observed in southern Maryland counties and a comparison of the two databases is made (as of January, 2020). As was done with the previous families, I have included with each species a note extracted from the book “Natural History of DelMarVa Dragonflies and Damselflies” by Hal White (reference 1). Of particular relevance for Calvert County, I have also included information on the single species of this family that was observed at the Cove Point LNG Property and reported in “2011-2012 Survey of the Dragonflies and Damseflies (Odonata) of the Cove Point LNG Property (Calvert County, Maryland” by Richard Orr (reference 2).

Stream Cruiser/Didymops transversa
Unlike their larval forms, adult dragonflies and damselflies do not walk. The adult legs are adapted for perching and catching prey, but not walking. (1)
Cove Point adult abundance and flight period – uncommon/21-Apr to 10-May. (2)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – present ​ Charles - present

Georgia River Cruiser/Macromia illinoiensis georgina
S3 Watch List (see below for definition)
The Georgia River Cruiser is almost indistinguishable from a closely related subspecies, the Illinois River Cruiser. The Illinois River Cruiser can be found in fast flowing streams of the Piedmont while the Georgia River Cruiser prefers slower moving Coastal Plain streams. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – present​ Charles - present

Definitions from the Maryland Department of Natural Resources “List of Rare, Threatened, and Endangered Animals of Maryland”:
S3 - Vulnerable / Watchlist — At moderate risk of extinction or extirpation due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors. Typically occurring in 21-80 populations.

Posted by rosalie-rick rosalie-rick, February 11, 2020 18:23

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