I found this Scarlet-bodied Wasp Moth Cosmosoma myrodora in the shade near the main path at Estero Llano Grande State Park/WBC, Hidalgo County, Texas on October 20, 2009. Luckily it did not move around much and I was able to show it to all the interested staff and visitors that afternoon. The male of his species applies a coating of toxins to the female to protect her during mating and egg-laying - the only known insect in the world to do this; check out this article for more details.
This uncommon taxon is native to the coastal strip of the Gulf of Mexico and coastal Atlantic Florida; there are records for a mere handful of Texas counties, and this seems to be only the second documented occurrence in the Lower Rio Grande Valley. There were three seen at the same location on the following day: