Caccothryptus larryi

Caccothryptus larryi is a species of minute marsh-loving beetle in the subfamily Limnichinae. The species was described alongside five other Caccothryptus species by Natural History Museum entomologist Keita Matsumoto in 2021, using specimens gathered in 1953 by Harry George Champion in Haldwani, India. Both of the c. larryi specimens featured genital structures distinct from Champion's initial classification of C. ripicola. The species was named for Larry, the Chief Mouser to the Cabinet Office at the British Prime Minister's residence at 10 Downing Street.

Taxonomy
The Limnichidae (minute marsh-loving beetle) genus Caccothryptus was first described by David Sharp in 1902. In 2014, the genus was divided into five species groups by Carles Hernando and Ignacio Ribera, as part of a reorganization which brought the genus from seven to 23 species.

A group of Caccothryptus specimens were collected in 1953 by forester Harry George Champion in the Haldwani division of the Kumaon Himalayas, India. These were labeled as C. ripicola, which Champion had previously described in 1923. These were stored at the British Natural History Museum. In 2021, Natural History Museum entomologist Keita Matsumoto identified a number of distinct species from these specimens. Two specimens, a male and a female, were identified as a distinct species and became a holotype and paratype for Caccothryptus larryi. C. larryi was placed in the species group compactus and named for Larry, a cat serving as Chief Mouser to the Cabinet Office at 10 Downing Street since 2011.

Description
Both Caccothryptus larryi specimens identified have an elytral length of around 2.5 mm, and elytral widths of around 2 mm. Their prothoraces both measured around 0.75 mm in length and 1.7 mm in width. The female paratype is slightly larger in all measurements. C. larryi 's body is dark brown and covered with long, light yellow setae. Its tarsi are divided into five segments, of increasing length, with the fifth segment as long as the others combined. It has long, narrow, light brown tarsal claws. The beetle's head, smooth and punctured, is slightly retracted into its pronotum, and features eleven-segment antennae. Little sexual dimorphism exists between the male and female specimens, beyond a longer fifth abdominal ventrite on the female.

The beetle's genitals display a number of differences from the original classification of C. ripicola, which enabled its classification as a separate species. C. larryi parameres have oval-shaped notches on the upper side, as opposed to ripicola 's semicircular notches; they also feature asymmetrical notches on the side of the median lobe, and are generally wider and shorter. The depression between larryi 's parameres are narrow and elongated with a pointed end.