Occasional Papers of the Musetmi of Zoology 7 



have them determined by a speciaHst. In the present list 

 somewhat less than 40 per cent of the species collected have 

 been determined, and largely because of the difficulty of deter- 

 mination no particular effort has been made to collect mem- 

 bers of this group. It would appear to be proper, therefore, 

 to omit them in the comparison of lists by different collectors. 



Of the 285 species of moths, exclusive of the Tineoidea, 

 in the three lists, 38 have been taken only at Douglas Lake, 

 52 only at Whitefish Point, one only in Gogebic County, one 

 only in Marquette County, and 117 only in the vicinity of the 

 Straits. Out of 283 species, only 74 have been taken in more 

 than one of the three localities for which there are extended 

 lists, and only 18 have been taken in all of the three. The list 

 for the Straits of Mackinac includes 49 species that were 

 recorded from Douglas Lake and 40 species that were noted 

 from Whitefish Point. Only five species are listed from 

 both Douglas Lake and Whitefish Point that were not taken 

 at the Straits. 



The same phenomenon will be noted if the distribution of 

 species from the different counties included in the Straits list 

 is studied, although not to quite such a degree. The majority 

 of the species have been taken in but one county. A further 

 fact bearing on the subject is to be found in the great number 

 of species that are represented by only one or two individuals. 

 Purthermore, each year of collecting adds twenty to thirty 

 new species from the same localities. In view of these facts, 

 any further comparison between lists of this nature would lead 

 only to what probably would be erroneous conclusions. 



Two explanations are possible. First, that the distribution 

 of the species of Heterocera is not at all uniform, species 

 being confined to certain localities with very narrow limits, 

 although such localities may be rather widely scattered over 



