Mating March Flies

I came upon an interesting sight the other day: two flying insects sat on the white lawn-bench in our backyard, attached together by the ends of their abdomens. I knew instantly that they were mating but didn't have the slightest idea of their identity. So, after much research, I determined that they were March Flies, also called Lovebugs (Plecia), St. Mark's Flies (esp. Bibio), Fever Flies (esp. Dilophus), and Garden Flies. March Flies are members of the family Bibionidae. I haven't been able to pinpoint the genus because I didn't know what to look for and consequently didn't get the needed close-ups. I'm guessing they belong to either Bibio or Dilophus.

March Flies are interesting because of the characteristics distinguishing the sexes. While, like most insects, the female is larger, she has smaller eyes than the male and a longer head. The male, though smaller in body, has enormous compound eyes comparable to those of a stereotypical fly. These specimens were obviously members of an autumn generation, for most species also have a spring one (hence the name "March" Fly). After mating, the female will lay 200-300 eggs and die soon after. Such is the life of an insect.

I purposely focused on the mating region this time, so that's why the heads are out of focus.

What was funny about this was that while mating the flies cleaned their legs and eyes. I've also read that these flies can mate and fly at the same time. Now, that's what I call multitasking!

References:
http://crawford.tardigrade.net/bugs/BugofMonth03.html (March Flies in general)
http://bugguide.net/node/view/3834 (Bibionidae)
http://bugguide.net/node/view/12765 (Bibio)
http://bugguide.net/node/view/12764 (Dilophus)
http://www.puyallup.wsu.edu/plantclinic/resources/pdf/pls7marchflies.pdf