32 University of Michigan 



Microtiis pcnnsylianiciis pcnnsylvanicus. Meadow vole. 



Mud-flat, 6. Arbor-vitae swamp, i. 



Tall-sedge, 28. Leather leaf bog, 15. 



Grassy-meadow, 6. Sphagnum bog, g. 



Black ash swamp, i. Black spruce — tamarack bog, i. 



Shrub stage, 17. 



Sixty-five were taken in the Cisco Lake Region and 19 in 

 Ontonagon County, near Gogebic Lake. It is most abundant 

 in grassy and sedgy meadows and in open bogs, though it is 

 found rarely in swamps and tree-covered bogs. The individual 

 listed from the arbor-vitae swamp was taken in a young growth 

 of arbor-vitae, black spruce, hemlock, and many alders, and 

 not in typical arbor-vitae swamp habitat. Of the 17 listed from 

 the shrub stage, one was taken in a wet, sedgy part of a shrub- 

 covered burn at Poor Lake, and the others were secured in 

 the shrub and grass clearing around the camp house on Lindsley 

 Lake. 



Of ten feinales examined, July 10 to September 5, one con- 

 tained 3 embiyos, one 4 embryos, and two 5 embryos each. 

 September 5 was the last date on which embryos were found. 

 The three embrj-os found on the last date were each 23 mm. 

 in length and together they weighed 8.5 grams, which Avas 

 26 per cent of the weight of the mother with the embryos 

 removed. 



Both adults and immature young were seen moving about, 

 and were also trapped in broad daylight, but it is more active 

 in the evening just before sunset. 



A captive juvenile was placed July 19 in a large tub with 

 an adult female, which might have been its mother, for both 

 were taken on succeeding days in the same trap. The young 

 one iinmediately tried to nurse, but was severely bitten and 

 driven away, though it made numerous unsuccessful attempts 

 later. When approaching the old female the baby frequently 



