Novitates Zoologicae XXXV. 1929. 155 ON FLEAS COLLECTED BY DR. H. M. JETTMAR IN MONGOLIA AND MANCHURIA IN 1927 AND 1928. By DR. KARL JORDAN. (With Plates VII to X.) rPHE species of Siphonaptera are evidently very numerous in Siberia and the adjacent districts of Asia. Although Drs. Wagner and Joff as well as ourselves have already described a good many species from that region, the collections dealt with in the present paper prove that the flea fauna has as yet only been sampled. As Dr. Jettmar, to whom we are much indebted for these valuable collections, has formerly sent us material from Transbaicalia, we are now in the position to study the geographical variation of at least some of the Palaearctic Asiatic species. The study of the transmission of diseases, which is so closely linked up with the knowledge of the Ectoparasites which act as vectors or which are potential vectors, we find to be of the greatest assistance to the systematist by furnishing material, a fact we gratefully acknowledge. On the other hand, the collectors of warm-blooded Vertebrates for systematic purposes, who should and might be the chief source of increase in our knowledge of the species of Ectoparasites, as a rule neglect to collect the Arthropods occurring on the mammals and birds obtained, lack of time frequently combined with a narrowness of outlook preventing the collector from going beyond the amassing of skins. Fortunately, there are pleasing exceptions. The descriptions we give of new forms are as much as possible restricted to essentials sufficient for the purpose of identification and classification. De-tailed descriptions will appear in the monograph. When giving the limits of variability, particularly in the case of bristles, it must be understood that the bristles have been counted only in a limited number of specimens and that therefore the numbers given are approximative. I. Manchuria : Excursion to Tungliao in Southern Manchuria, November 1928. l. Ceratophyllus tesquoruin sungaris subsp. nov. (PI. VIII, figs. 9 & 10, 3d). Near to C. t. mongolicus J. & R. 1911 ; differs in the exopodite F being more rounded posteriorly, with the apical margin more slanting than in the various other known subspecies. Our figures represent extremes ; fig. 10 taken from type of sungaris. A series from : Sand dunes near Ta-Lin, on Cricetulus arenarius and in its burrow ; sand dunes near Chendjatien, in burrows of Spermophilus (probably S. mongolicus) ; Tungliao, in abandoned burrow of Spermophilus or Zapus. 2. Ophthalmopsylla kukuschkini Joff 1927. 2 3 <$ from sand dunes near Chendjatien, in burrows of Spermophilus (prob-ably S. mongolicus) ; and 1 $ from the same place in nest of Cricetulus griseus fumatus.