368 R. W. GLASER AND J. W. CHAPMAN. 



flacherie, lethargia, maladie de morts-blancs, schlaffsucht, faul- 

 sucht, fettsucht, polyhedral disease, wilt, wipfelkrankheit, jaun- 

 dice and gelbsucht. 



We do not wish to dwell upon the differences or similarities 

 between all of these maladies, but will confine ourselves solely 

 to the group of polyhedral diseases under which are included the 

 four commonest manifestations, viz., wilt, wipfelkrankheit, jaun- 

 dice and gelbsucht. Wilt is the vernacular term used in America 

 for the polyhedral diseases. It is a name suggestive of post- 

 mortem aspects, but unfortunately a number of caterpillar 

 diseases distinct from wilt on superficial examination also have 

 a similar post-mortem appearance. Moreover, a number of 

 diseases common to plant pathology are labelled with the same 

 term. We do not think it wise to eliminate the name, however, 

 for the reason that it has been used so long and "wilt" certainly 

 means more to field entomologists and foresters than "polyhedral 

 disease" which is only significant to laboratory workers. The 

 term "Wipfelkrankheit," which is used for a similar affection of 

 nun moth caterpillars in Germany, is a very suggestive name 

 for the reason that when the animals are in the last stages of the 

 disease, they congregate in masses at the tops of the trees or 

 "wipfeln" and die hanging by their prolegs. The name "Wip- 

 felkrankheit" has the further advantage in that it is not applied 

 to any other plant or animal disease. "Gelbsucht" or "jaun- 

 dice" are terms used to designate a polyhedral disease in silk- 

 worms. The two terms are descriptive of the clinical picture 

 of the diseased worms and are not used for any other affection 

 known to pathology. 



The larval stages of the following species of lepidoptera have 

 been examined by us and found to be susceptible to the poly- 

 hedral diseases. Animals which can only be infected experi- 

 mentally have been omitted, i. e., the list comprises only those 

 which besides being capable of experimental infection also have 

 the disease or diseases in a state of nature. 



I. Saturnidae. 



1. Hemileuca maia Drur. 

 II. Arctiidse. 



2. Apantesis virgo Linn. 



