Jigger (sand flea) infested foot. Tunga penetrans (chigoe flea or jigger) is a parasitic insect found in most tropical and sub-tropical climates. It is native to Central and South America, and has been inadvertently introduced by humans to sub-Saharan Africa. Synonyms for Tunga penetrans include Sarcopsylla penetrans, Pulex penetrates, and many others. In its parasitic phase it has significant impact on its host, which include humans and certain other mammalian species. A parasitical infestation of T. penetrans is called tungiasis.
According to data provided by the U.S. Navy Oceanography Portal (http://www.usno.navy.mil/USNO/as...), astronomical twilight lasts much longer (nearly 2 hours) during the summer compared to the winter months (only about 30-40 minutes).
The time just after sunset, when the light is half-faded, but the world is not yet totally dark, is twilight. If you are between two states, like asleep and awake, that can also be called a twilight moment. Twilight comes just before the night falls. The early light, just before sunrise, is also technically called twilight but most people call it dawn.. The prefix twi- might be a clue that twilight happens twice a day, or it could mean half, as in the half-light of this time.