A Revision of the Genus Malacosoma Hiibner 

 in North America (Lepidoptera: Lasiocamp- 

 idae): Systematics, Biology, Immatures, and 



Parasites 



By 



Frederick W. Stehr 

 and 

 Edwin F. Cook ^ 



Introduction 



The genus Malacosoma Hiibner, the tent caterpillars, is a group of 

 lasiocampid moths restricted to the temperate regions of the Northern 

 Hemisphere. The adults often are ignored, possibly because they are 

 quite abundant (collectors tend to save rare or unusual specimens), 

 are moderate in size, comparatively drab in color, and have a lifespan 

 of only a few days at the most. The larvae, however, are well known 

 for the conspicuous tents (i.e., webs, nests) which some species construct 

 in early spring soon after the first leaves appear. The hordes of cater- 

 pillars (sometimes incorrectly called "armyworms") are perhaps the 

 best-known life stage to the layman. 



This present study of the genus Malacosoma Hiibner in North America 

 is modified from a Ph.D. thesis by Frederick W. Stehr which was sub- 

 mitted to the University of Minnesota in 1964. The literature was 



' Department of Entomology, Michigan State University, East Lansing, Michigan 

 48823. 



2 Department of Entomology, Fisheries and Wildlife, University of Minnesota, 

 St. Paul, Minnesota 55101. 



Paper No. 6172, Scientific Journal Series, Minnesota Agricultural Experiment 

 Station, St. Paul, Minnesota 55101. 



Published with the approval of the Director of the Michigan Agricultural 

 Experiment Station as Journal Article Number 4110. 



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