On the morning of Oct. 16, three women joined the crowd of worshipers entering a mosque in the Umarari Molai suburb of Maiduguri, Nigeria, for morning prayer. Beneath their clothing, each had an explosive device strapped to their chests, and within minutes of their entry three bombs ripped through the mosque, leaving 26 dead. The attack was the second of three suicide bombings that wracked Nigerian cities within three days. All were the work of Wilayat al Sudan al Gharbi, the group formerly known as Boko Haram before it pledged fealty to the Islamic State in March 2015. By our count, Wilayat al Sudan al Gharbi has mounted more suicide bombings this year than any other jihadist group except the Islamic State core in Iraq and Syria. But whereas the Islamic State core group overwhelmingly uses male bombers, nearly half of Wilayat al Sudan al Gharbi's bombers have been women.