Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Genus Chrysomya - Hairy Maggot Blow Flies

red-eyed fly - Chrysomya megacephala Hairy Maggot Blow Fly - Chrysomya megacephala - female Hairy Maggot Blow Fly - Chrysomya megacephala - male Diptera - Chrysomya megacephala - male Chrysomya - Chrysomya megacephala - female Unknown fly - Chrysomya megacephala Diptera Q1, ID please - Chrysomya megacephala - male Female, Lucilia? - Chrysomya rufifacies
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon (Calyptratae)
Superfamily Oestroidea
Family Calliphoridae (Blow Flies)
Subfamily Chrysomyinae
Genus Chrysomya (Hairy Maggot Blow Flies)
Explanation of Names
Chrysomya Robineau-Desvoidy 1830
2 spp. in our area, a dozen total(1)(2)
Robust metallic green flies with a distinct blue hue when viewed under bright sunlit conditions. The posterior margin of the abdominal tergites are a brilliant blue.
Basal section of the stem vein, when viewed dorsally, setose; dorsum of 1st and 2nd abdominal tergites black, posterior margins of abdominal tergites 3 &4 black(1)

Edit TT: Decent close-up shots of anterior thoracic spiracle and head and are needed to ID an individual to species, viz:
- vestiture of anterior thoracic spiracle: dark brown or dark orange in megacephala; looks like this may be an orange spiracle
spiracle pale or white in rufifacies;
- genal dilation with orange ground colour and orange setae in megacephala; genal dilation with pale dusting and pale setae in rufifacies.
Male eyes are perhaps the most useful character, viz:
- upper facets enlarged and sharply demarcated from smaller facets in lower third of eye in megacephala

- eye facets small throughout in rufifacies;
- frons very narrow with eyes nearly touching megacephala see thumbnail under eye facets;
- frons broader rufifacies

Another distinguishing feature between the 2 spp. maybe eye colour (in live flies);c. megacephala appears to have bright red/orange eyes whereas rufifacies has browner brick-red eyes. This feature is not mentioned in any of the keys I have seen; probably because the dipterists have been working with pinned material with faded eyes. (TT)
native the Old World, adventive in our area (so. US to IL-MI) and Mesomerica(1)