96 BULLETIN UNIVERSITY OF MONTANA 



Special Studies, 



Among the other groups special study was made on shells and dragon- 

 flies. Shells in the State of Montana are relatively scarce. Few reports 

 have been made on shells taken from this region. The only list so far 

 available is the one given in Nautilus, Vol. VIII, p. 63, giving a list of 42 

 species from the Missouri river. The material from the western side of 

 the range lists 21 species. The conditions in the State of Montana are 

 not favorable to the growth of shells. The rivers are rapid, with scarc- 

 ity of food, and with little lime. The lakes contain clear cold water, 

 are usually deep, with few swampy places, and with rocky shores and 

 bottoms. The marshy stagnant portions of the lakes are usually small, 

 and liable to dry up in summer. The mountain sides in summer become 

 dry and parched, except in protected portions and along streams. Great 

 stretches of plain are without moisture for a portion of the year, and 

 almost every living thing that cannot move to the water courses is killed. 

 The days in summer are hot, the nights cool. The air is dry and evapor- 

 ation is rapid. As a result of the above conditions we may expect great 

 variation of species in adjacent regions, where the barriers may be suffi- 

 cient to cut off all communication between the regions. It is hoped by 

 making extensive collections of land and fresh water shells to secure 

 sufficient material to throw some light on the geology of the region, which 

 now offers many difficult and complex questions. One new species has 

 been discovered, and the first living specimens secured. Another has 

 been found at an altitude of 9,000 feet. In the report of the work on the 

 lakes following information is given regarding the limited number of spe- 

 cies found in each. 



The work on Odonata has been prosecuted with more or less vigor 

 during the past four years, besides material taken at different portions 

 previous to that time. The result is the discovery of about fifty species 

 in the state, which is not a large showing. The same conditions making 

 it difficult for shells to grow in the waters of the state will apply to drag- 

 onflies. The young live in water, which must not be swift nor too 

 clear, but must offer sufficient animal food to keep the larvae alive, must 

 be stagnant enough to support life of such slow and uncouth water dwellers 

 and must offer them suitable hiding places to keep out of the sight and 

 reach of enemies. Such places are not common. In Illinois the writer was 

 accustomed to visiting the ponds around town, taking as many as 25 spe- 

 cies in a single afternoon. In Montana a hard and long day's work has 

 resulted in but six species, and not many specimens of these. From this 

 it will be seen that dragonfly collecting in the state is not only difficult, 

 and the results meager in amount of material, but from what has been 

 said there is a possibility of securing many new and interesting things. 



During the three seasons of collecting in the western part of the state 

 large numbers of botanical specimens have been secured, which are de- 

 posited in the herbarium of the University, and await study. 



It will now be helpful to the reader to give some information 

 concerning the region under discussion, which will convey a better idea 

 of the country than has heretofore been given. 



