Subject: A Robber Fly ?
Geographic location of the bug: Yelapa, Mexico-about an hour south of Puerto Vallarta
Time: 09:09 PM EDT
Your letter to the bugman: Hello, This very loud buzzing insect was in my room at night. It flew with its head up and tail hanging down at the ceiling. It was chasing/harassing geckos. The geckos left my room for two nights following. I captured it to look at it and released it in the daylight. It flew straight up. I did not get a good daylight photo but here it is on my curtain in the early morning.
How you want your letter signed: Cody Sontag
This looks to us like a Ship Timber Beetle in the genus Atractocerus. According to Beetles in the Bush: “Placed in the family Lymexylidae (ship-timber beetles), species in this genus look less like beetles than they do large flying ants or strange damselflies due to their highly reduced elytra that expose their greatly elongated abdomen and leave the hind wings uncovered. The hind wings also are unusual in that they are held fan-like in repose rather than folded as in most other beetles.” The site continues: “Adults are attracted to light at night …. Nothing is known about the biology of Atractocerus, but larvae of other genera are reported to bore into hardwoods and palm stems (Picker et al. 2002). … The large eyes of Atractocerus, however, suggest a predatory lifestyle. The common name of the family originates from a northern European species that has in the past been a destructive pest of ship timbers.”