1924 ENTOMOLOGICAL SOCIETY 67 



GENERIC KEY TO THE PUP^E OF COSSID^ OCCURRING 

 IN NORTH AMERICA. 



As will appear from the following key, the pupal cases of Prionoxystus 

 are easily distinguishable from those of other cossid genera. 



A. Abdominal spines irregular in shape and equal in size on both cephalic 

 and caudal rows. — Zenzera. 



AA. Abdominal spines regular, larger in cephalic than in caudal row. 



B. Cephalic spines pyramidal in outline. — Acossus. 

 BB. Cephalic spines flat; spear-shaped. — Prionoxystus. 



The writer is indebted to Mr. J. J. de Gryse for criticisms and suggestions. 



NOTES ON LICE WITH SPECIAL REFERENCE TO THE CHICKEN 

 LOUSE (Lipeurus heterographus) 



Dr. A. R. Wickware, Health of Animals Branch, Dominion Department 



of Agriculture, Ottawa 



Insects are usually regarded as ubiquitous parasites whose persecutions, 

 while annoying and distracting, are of little moment from the standpoint of 

 general health. 



This viewpoint, per se, appears more or less correct, but when considered 

 in relation to infectious diseases, as vectors or intermediate hosts, their presence 

 portends an ominous state of affairs fraught with grave possibilities. 



Lice appear to be the least harmful of the insects, yet experimental evidence 

 incriminates several varieties in the transmission and propagation of specific 

 maladies. 



Thus it has been conclusively demonstrated that the causative organism 

 (Spirochete recurrentis) of relapsing fever is transmitted from man to man through 

 the intervention of two species of human lice, Pediculus capitus and Pedicuhis 

 vestimenti. 



The findings of the Royal Commission appointed to investigate trench fever 

 also incriminate the human head louse, Pediculus capitus, in the transmission of 

 this malady, while the clothes louse, Pediculus vestimenti, is a known carrier of 

 typhus fever. 



In view of the foregoing it is reasonable to expect that future research will 

 establish a connecting link between many of the infectious diseases of domes- 

 ticated animals and the lice parasitic upon them. 



Apart from their role in the transmission of infectious disease, what harmful 

 influence do lice exert on the host, when viewed from a purely parasitic stand- 

 point? It is generally agreed that a more or less intense pruritis or cutaneous 

 rash is caused by the presence of lice upon the body, varying according to the 

 number and variety as well as the age and condition of the infected animal. 

 Their presence upon young animals is supposed to result in a stunted growth, 

 while older animals harbouring them become emaciated and unthrifty. Whether 

 they alone are capable of producing death by irritation without the intervention 

 of some contagious disease is problematical. 



