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March Fly - Penthetria heteroptera - male

March Fly - Penthetria heteroptera - Male
Amherst, Massachusetts, USA
September 20, 2004
Shot in our backyard. I only have a simple knowledge of fly families, so any help would be appreciated:)

I am also guessing it is a male on the basis of the large compound eyes which usually differentiates the sexes in other fly species. So feel free to correct me if I am wrong.

Moved from March Flies.

March fly?
Reminds me of a male Bibionidae, or "march fly." Did not know you could find them in the fall, though:-)

Hey Eric,

That was my first guess, but it is kinda late in the year for them...hmmmm.

Some March Flies fly in fall
Hannah has posted a photo of a pair of Plecia mating in September in Florida.

I just looked in Brimley, p. 328 (1), and he records "Plecia heteroptera" (synonymn for P. nearctica or the americana, I presume) as being collected in October in Raleigh and Southern Pines, North Carolina. Various species of Bibio are also listed as flying in the fall.

Brimley is good on phenology. He records dates of occurence for almost everything. A nice touch--not present in many other guides.

Patrick Coin
Durham, North Carolina

"Love Bugs"
These (Hannah's photo)are very common in the New Orleans area every September. In fact, they swarm. I remember that, as a child I would see them every year around the time that school started, and I'm still seeing them, too many years to mention later. They are locally called "love bugs" and are always mated. I never have noticed them around at any other time of the year. Unfortunately, they get smashed on windshields and front bumpers of cars and make a mess. I was just thinking about what they might be classed as scientifically so I looked them up on the guide just now.


Re: Some March Flies fly in fall
In our part of Europe we have three bibionids that are present later in the year, one species of Dilophus and two of Bibio. The other genera, Plecia and Penthethria, are represented by one species of the latter genus which is active early in the year. This is not Dilophus or Bibio (they are morphologically very different) so I would say a different family.


Hmm...I have been seeing very similar mated pairs...
...recently - in May in New Orleans area, where I only remember seeing them in the fall. (See my earlier post below). So there must be several similar species here as well. I will leave the fine points as to which is which to those more experienced. But I thought something climate-wise was off and the bugs got "confused", until I read the recent posts here. I was worried about global warming, so thanks.

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