Latrodectus tredecimguttatus, sometimes known as the Mediterranean black widow, the European black widow, or the steppe spider, is a species in the genus Latrodectus (widow spiders). It is commonly found throughout the Mediterranean region, ranging from Portugal to southwest and central Asia, hence the name. Specimens from central Asia are also known by the binomial name Latrodectus lugubris; that name, however, is now considered improper, though it is still commonly found in the literature. Latrodectus tredecimguttatus was previously considered a Latrodectus mactans subspecies.
L. tredecimguttatus bears different names in different regions. For example, in Southern France it is called Malmignatte and in Italy is called malmignatta. Throughout the Central Asia and Eastern Slavic region, the name karakurt is most often applied. The words kara, meaning "black", and kurt, meaning "wolf" (the word also means grub worm or maggot, which the spider is most likely named for), come from the Turkish language (Turkic languages).
"Karakurt" is the twenty-first episode of the second season of the American crime drama The Blacklist. The episode premiered in the United States on NBC on May 7, 2015.
The task force investigates a Blacklister named "Karakurt" who is targeting a U.S. Senator using a deadly biochemical weapon that is transferred via touch. Later on, Liz and Ressler think they have rescued the Senator from being infected by Karakurt. However, as they later learn, Liz is the one who unknowingly infected the Senator (during the rescue). Once the discovery is made, the Kabal sets a plan in motion to frame Liz, under the guise that she sympathisizes with her Russian spy mother (a discovery that Liz herself also learns about her mother). Elsewhere, Tom tries to mend things with Liz.
"Karakurt" premiered on NBC on May 7, 2015 in the 9–10 p.m. time slot. The episode garnered a 1.4/5 Nielsen rating with 6.90 million viewers, making it the third highest-rated show in its time slot behind ABC's Scandal and CBS's The Odd Couple. It was also the twenty-ninth highest-rated television show of the week.