1 8 Proceedings . 



is constantly increasing. In the wings we have good characters for genera 

 and higher groups, but usually of little use for species. The relative length of 

 the joints of the antennae are subject to too great variation to be much relied 

 upon. A knowledge of the food-plant is not sufficient as exceptions are con- 

 stantly being brought to light. Color is in all the larger genera, where spe- 

 cific characters are most needed, of little value. It therefore, in many cases, 

 becomes necessary to seek for additional characters to those commonly 

 given. 



A stud3'^ of mounted specimens imder the microscope brings out several 

 characters that promise to be of great value, at least for the more difficult 

 genera, one of the most important of which are the sensoria, or small sense 

 spots distributed over the surface of the antennae, which have been found 

 quite constant, both in size, number and distribution. A summary of the 

 results of a study of the sensoria of the Minnesota species was given; a 

 full account of which will appear in a final report on this family in the pul)- 

 lications of the Geological and Natural History Survey of Minnesota. 



A new locality for cobalt in Minnesota, by A. D. Meeds. 



[abstract.] 

 While examining a sample of manganese ore from Monticello, Minn., in- 

 dications of cobalt w^ere noticed and further examination proved it to be 

 present in small quantity. As cobalt had not been reported from Minnesota 

 before, so far as known, a determination of the cobalt was made. The ore 

 under examination was a bog ore and contained much organic matter. It 

 was first ignited and the ash submitted to partial analysis, resulting as 

 follows: 



Manganese, Mn., 35.70 



Iron and Alumina, AiaO:,,.FeoO;i, 4.63 

 Cobalt Oxide, Co 0, 071 



Insoluble, Si Oo, 28.33 



Cobalt in small quantity seems to be quite constant in its occurrence in 

 bog manganese ores and its appearance here is not surprising. 



Although a number of samples of manganese ore from Monticello have 

 been examined, this is the only one so far that has shown any sign of cobalt. 

 This paper was discussed briefly by H. V. Winchell, w^ho stated that re- 

 cently obtained samples of pyrrhotite from the lower part of the Huronian 

 series near Gunflint lake, T. 65, R. 4 W., had been found to contain traces 

 of cobalt and about three per cent, of nickel. This is supposed to be at the 

 same geological horizon as the Sudbury, Ont., nickel deposits. 



The Fauna of the Magnesian Series of the northwestern 

 states; with descriptions of new species by F. W. Sardeson. 

 [See paper F.] 



The structure, lithology and genesis of the Magnesian 

 Series of the northwestern states, by C. W. Hall. [See 

 paper G.] 



Supt. Robert P. A. Nix, New Ulm, Minn., Prof. W. V. 



