Atalanta (1887–1898) Lang is, at least, advertised as a forthcoming contributor in the St. James’s Gazette advertisement of the first number of this periodical (20 Sep. 1887, p. 16). The Atalanta was initially edited by L. T. Meade and Alicia A. Leith.
Internet Archive has scans of several of the volumes, but I have not yet traced Lang’s contribution(s). (Wikipedia claims Lang contributed an article on Sir Walter Scott.) The list of contributors in the volumes below, however, is quite worth looking at—Robert Louis Stevenson and E. Nesbit, among others.
Vol. 2, October 1888–September 1889.
Vol. 4, October 1890–September 1891.
Vol. 5, October 1891–September 1892.
Vol. 6, October 1892–September 1893.
Vol. 7, October 1893–September 1894.
Vol. 8, October 1894–September 1895.
Vol. 10, October 1896–September 1897.