PROCEEDINGS, 1921 



33 



The lower slopes and benches of the river valleys are very much 

 warmer than the upper tableland and are covered with tall bunch-grass 

 and Chrysothamnus bushes, and are intersected by numerous ravines 

 filled with rank herbage and small trees. It is here that we find the 

 phytophilous campestrian species, whose habitat is a warm, dry loca- 

 tion, plentifully covered with herbage such as the tall bunch-grass of 

 the open slopes, or the tangled brush of the ravines. The colder and 

 higher tableland above supports but little vegetation and has been so 

 heavily overgrazed by cattle that we find nothing but a scant covering 

 of low-growing grasses and small plants which soon dry up in the 

 summer sun. This is the home of the geophilous campestrian species, 

 whose favourite habitat is a bare, sunbaked ground devoid of all tall 

 herbage. 



The tableland is composed of a layer of lava rock overlying deep 

 beds of silt and gravel. The rivers in cutting down through this vol- 

 canic rock into the softer layers below, have left in many places, pre- 

 cipitous cliffs along the upper edges of their valleys (locally known as 

 "the rimrock"). At the base of these clififs there is the usual talus of 

 broken rock which reaches down on to the upper slopes of the valleys, 

 forming a favourable habitat for certain species which I am calling the 

 sa.vicoloiis campestrian . 



The forests, bounding the open country on the north, are composed 

 mainly of Douglas fir (Pseudotsuga mucronata), Engelmann spruce 

 (Picea engelmanni) and Lodgepole pine (Pinus murrayana). There is 

 very little undergrowth, the ground being covered with pine-grass. In 

 these forests we find the sylvan species. 



T*he semi-sylvan species are those which are found in the large 

 natural clearings in the forest, where an abundance of tall herbage 

 grows, and in the long grass beneath the aspen poplars which ai'e always 

 found fringing the edge of the forests and dividing them from the open 

 grass-land. The species included under this heading naturally overlap 

 the sylvan and geophilous campestrian species, but are never numerous 

 away from their natural habitat. 



Lastly, we have the hygrophilous group divided into the humicolous 

 species inhabiting hay-fields, borders of streams, the thick herbage of 

 "willow-bottoms," and the margins of lakes, and the paludicolous species 

 frequenting marshes and bogs. 



The following species were collected during the summer of 1920, 

 and are arranged systematically with short notes on their Ecological 

 Distribution. P^^^ily lqCUSTIDAE 



Anabrus longipes Caudell. Scmi-sykvn. Found inhabiting open 

 glades. Aspen groves on open mountain slopes, and in and around clumps 

 of trees on certain portions of the open range. 



Steiroxys (trilineata?) Thomas. A sciiii-syk'an species, fairly plenti- 

 ful, found in similar locations to Anabrus longipes. 



