"Illinois" Swift River Cruiser - Macromia illinoiensis illinoiensis (Walsh, 1862)

Range & Habitat:

The nominate northern race, it is found in northwestern New Jersey, replaced by the southern race on the coastal plain. Intergrades occur, especially in Somerset and Hunterdon counties.

Patrols along rivers and large streams.

Flight Season:
Early Date: 27 May
Late Date: 17 September

Flight season charts created from records in the official database maintained by Allen Barlow.

Male Dorsal - Photo by Jim Bangma
Click on a thumbnail to view full-size photo

Mostly blackish, with a single lateral yellow thoracic stripe, small spots on abdominal segments 1-4 and a large dorsal spot on S7. For comparison, see "Southern" Swift River Cruiser which is the southern race. The reduced abdominal spots are representative of the northern race. On the coastal plain, the Allegheny River Cruiser has a similar pattern to this form, but its range does not overlap in New Jersey. Caution: intergrades do occur from Hunterdon & Mercer through Monmouth. Not all can be identified as to type. More study is needed of this genus.


Conservation Status:
State: S4 Apparently secure in New Jersey
Global: G5T5 Secure globally, local taxon also secure