THE COLEOPTERA OF COLORADO. 223 



from that usually taken. There is of course that parallelism 

 between alpine and boreal productions which is due to con- 

 ditions of climate and temperature, so that generally speaking, 

 the ascent of a mountain takes us through a series of plants 

 and animals corresponding more or less closely to what we 

 should see in passing from south to north along the base of 

 the chain. However, migration up or down a mountain-side 

 is easy — often enforced by freshets or high winds — and 

 insects may occasionally occur in great numbers in situations 

 where they could not possibly breed. 



LIST OF LOCALITIES CITED, WITH APPROXIMATE ALTITUDES. 



While many of the altitudes here cited are not quite exact, 

 they are sufficiently accurate for our purpose. Some of the 

 data are drawn from the publications of the United States 

 Geological Survey, others from various railroad maps, and 

 the remainder are estimates or measurements furnished by 

 the collectors themselves. It must not be forgotten that the 

 actual altitude at which a specimen was collected may differ 

 by several hundred feet from that cited for the station, since 

 many of the towns are built on mountain-sides and a collector, 

 in order to save trouble, may label all of his captures alike. 

 Others adopt the plan of inclusive labelling, giving the ex- 

 tremes of altitude reached during work in a certain neighbor- 

 hood. 



In addition, I have appended to each station of importance 

 the name of the investigator, and where one of these localities 

 is cited in the following pages the credit of collecting must be 

 allotted accordingly. Some instances occur where a different 

 plan had to be adopted and in these cases the collector or 

 authority is mentioned directly in the proper connection. 



Alamosa. 755°°- Schwarz. 



Alma. 10,250. Bowditch. 



Arapahoe Peak. 11,000-12,000. Summit 13,520. 



Argentine Pass. 13,286. Bowditch and Wickham. 



Arkins. 6,000. O. E. Buffum. 



