1876.] 43 Pall. 



men, and other characters, readily distinguish this species from Tip- 

 ula Besselsi. 



Tipula nodulicornis Zett. 



Zetterstedt, Insecta lapponica, p. 841, 8. 



Diptera Scandinavian, x, p. 3934, 17. 



Stasger, Greenland's Antliater, p. 355, 15. 



The second Tipula which I found in Mr. Bessel's collection agrees 

 quite well with T. nodulicornis Zett. from Greenland. Unfortunate- 

 ly, only male specimens are at hand, and thus it could not be ascer- 

 tained whether the ovipositor is serrated or not, as seems to be the 

 case with that of Zetterstedt' s species (compare the description in 

 the Insecta Lapponica, which differs in some points from that in the 

 Dipt. Scandinavian). Mr. Schiodte, in his article on the Articulata of 

 Greenland, (in Kink's work; compare Berl. Entom. Zeitschr., 1859, 

 p. 152) considers the Tipula rivosa of O. Fabricius (non Linne), 

 Tipula arctica Curtis, Ins. Ross's Exp., and Tipula nodulicornis Zett. 

 as synonyms. 1 am inclined to admit the synonymy of the first 

 two species, but not that of the third. Curtis says of the abdomen : 

 " the incisures slightly ochreous," and also indicates this coloring in 

 the excellent figure he gives. 0. Fabricius says: "mas differt ab- 

 domine magis testaceo." The abdomen of the specimens from Polaris 

 Bay is of a uniform dull blackish gray. A comparison of Curtis's 

 and Fabricius's descriptions reveals several other coincidences, but 

 excludes the identification of the specimens which I have before me. 



Note on "Die Gasteropoden Fauna Baikalsees." 1 By Wm. 

 H. Dall. 



This paper gives the result of an exhaustive examination of a large 

 number of remarkable forms from Lake Baikal, one of which, Choan- 

 omphalus, had been generically separated by Gerstfeldt in 1859. 



Of the other genera Hydrobia, Ancylus, and Valvata have long been 

 established. 



The new genera proposed are Benedictia Dybowski, for a mollusk 

 with a limnaeiform shell and rudimentary operculum, two species of 

 which had been previously announced by Gerstfeldt and Schrenck as 

 Paludince. One new species is described. 



1 Anatomisch und systematisch bearbeitet, von W. Dybowski (Dec. 1875) Mem. 

 de l'Acad. Imp. des Sciences de St. Petersbourg, ser. VIII, t. XXII, No. 8 (cum 

 tab. VIII, lith). 



