Blue Bottle

Blue Bottle

Observation - Blue Bottle. Description: Maybe a Blue bottle fly but how can I seperate it from a Blowfly? And why is it not blue all over? And oh goodness - will I HAVE to try to understand these? postacrostichal bristles basicosta subcostal sclerite bucca lower calypter gena anterior s

Maybe a Blue bottle fly but how can I seperate it from a Blowfly? And why is it not blue all over?
And oh goodness - will I HAVE to try to understand these?
postacrostichal bristles
basicosta
subcostal sclerite
bucca
lower calypter
gena
anterior spiracle