6o 



TROPICAL MEDICINE AND HYGIENE 



form a row, which is readily seen with the naked eye even 

 in unstained specimens (fig. 27). In the mature segments 

 the eggs are contained in the uterus, and the mature seg- 

 ments are broader than they are long. 



Hymenolcpis nana is not a very rare parasite in man. It 

 is found in the United States of America, in Egypt, Japan, 

 and South America, as well as occasionally in Europe. 

 According to Foley, in Figing, Berbera, it is found more 

 common in children. In 16 children under 5 he found 

 it three times; out of 96 5 to 15 years old, once ; and in 

 none of 102 examined over that age. It is a very small 

 tapeworm, 15 mm. in length, and in its broadest segments 

 0-5 to i mm. in breadth. It has about 150 segments 

 (fig. 26). 



FIG. 26. Hymenokpis nana (v. Sieb.). About 12/1. (After Leuckart.) 



FlG. 27. Hymenolcpis diminuta ; two proglottides slightly enlarged. 

 The circular masses are the testes. (After Grassi.) 



It is 'closely allied, if not identical, with H. mnrina, 

 common in rats, and in that case the cysticercoid stage 

 is probably passed in one of the lepidopterous moths or 

 their larvae, which infest stored grain. It does not seem 

 to cause any symptoms in man. Treatment is unsatis- 

 factory, and complete expulsion of the worms difficult. 

 The prevention mainly turns on better storage of grain, 

 so that rats cannot deposit their faeces amongst it, and 

 in preventing moths having access to the grain ; possibly 



