Vespiform

Vespiforms were an insectoid race which had hives in the Silfrax Galaxy. (DW: The Unicorn and the Wasp) They were an ancient and wise race. (WEB: Captain Jack's Monster Files)

Biology
Vespiforms were a species of insectoids which resembled oversized wasps. Adults could measure around 3 metres in height. They were powerful creatures, with large stingers which could be regrown within hours of use. They had the ability to transform into the guise of other species. The transformations were accompanied by a glowing, purple-pink haze and left behind morphic residue. When in another form, Vespiforms were genetically compatible with the mimicked species. This allowed them to interbreed with members of any other species.

Technology
Sometime prior to Earth's 19th century, the Vespiforms developed intergalactic space travel. This capacity allowed at least one of the species to travel from the Silfrax Galaxy to Mutter's Spiral. Once there, at least one Vespiform went to Earth, presumably for the purposes of research. (WEB: Captain Jack's Monster Files)

Vespiforms also had telepathic recorders. These devices held the essence of the Vespiform cultural heritage, and served as a sort of "instant school". The entirety of what it meant to be a Vespiform could be transferred from the recorder to the mind in a matter of seconds. But the device also transferred the thoughts of any being in very close proximity to it as well. Were the thoughts of a non-Vespiform to blend with the information contained in the recorder, the results could be unpredictable. (DW: The Unicorn and the Wasp)

History
Very little was known of the history of the species itself. Jack Harkness heard whispers of a war between Quark rebels and Vespiforms (TVC: The Killer Wasps), but he could not confirm these stories. (WEB: Captain Jack's Monster Files) If true, it implies a common link between the Vespiform and the Giant Wasps.

Contact with Humans
In 1885, the Vespiform (simply known as Christopher) met Clemency Eddison in India and had a child with her. He gave her a large, purple crystal set in a necklace, which she later came to call "the Firestone". When he soon thereafter drowned in the monsoon of that year, the Firestone became her only memory of him, and she wore it often.

Some months later, Clemency gave up the child of their union for adoption, because the morés of the time frowned upon unwed parenting. The child eventually became a reverend, Arnold Golightly, who became a vicar in the parish that included the Eddison's estate. At the age of 40 in 1926, he had discovered his Vespiform nature. Because of his newfound proximity to the Firestone — in reality a Vespiform telepathic recorder — his Vespiform cultural heritage was automatically transferred to him through the device. But the transfer also included some of its wearer's thoughts. Because she was reading an Agatha Christie novel at the time of the transfer, Golightly took on board some of the aspects of the characters in the novel. Hence, Golightly started committing various murders in the style of an Agatha Christie novel. The Doctor, Donna Noble and Agatha Christie herself were able to discover his crimes, and force Golightly to publicly reveal his Vespiform nature. Ultimately, Donna kills him by throwing the Firestone into the lake. Golightly followed and drowned, but relieved Agatha of his connection with her in his dying moment. (DW: The Unicorn and the Wasp)

Long after the events at Eddison Hall, the Firestone was dredged up from the bottom of the lake and sold at auction to Jack Harkness. In the 21st century, he claimed to be in possession of the only Vespiform telepathic recorder known to exist on Earth. (WEB: Captain Jack's Monster Files)