Contents 



Page 



Introduction 1 



Acknowledgments 2 



History of the Classification of Malacosoma in North America .... 4 



Summary of results 6 



Economic importance of genus Malacosoma 8 



Life cycle 13 



Methods 14 



Equipment 15 



Field collecting 16 



Disease 18 



Parasites 20 



Egg masses 20 



Tents 25 



Cocoons 33 



Adults 34 



Male terminalia 37 



Female terminalia 39 



Larvae 39 



Chaetotaxy 39 



Color pattern 41 



Variability in larvae of M. californicum 44 



Sexing larvae 46 



Experimental crosses 47 



Introduction 47 



Methods 47 



Results 49 



The pluviale-lutescens relationship 60 



F2 Egg Masses 63 



Summary of experimental crosses 64 



Genus Malacosoma Hiibner 66 



Key to adult male North American Malacosoma 69 



Key to adult female North American Malacosoma 73 



Key to mature larvae of North American Malacosoma 77 



Key to the egg masses of North American Malacosoma 83 



Malacosoma disstria Hiibner 84 



Malacosoma constrictum constrictum (Henry Edwards) 93 



Afalacosoma constrictum aus tritium Stehr 99 



Malacosoma tigris (Dyar) 102 



V 



