STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 53 



House-fly and Typhoid Fever: 



Much attention has been directed in recent years to the dangers of 

 the house-fly (Musca domestica) and other flies as agents in the trans- 

 mission of disease. All Public Health Departments now take cognizance 

 of the house-fly and issue warnings against its presence about the home. 

 Epidemics of typhoid and cholera in many cities, as well as the out- 

 breaks during the Spanish- American war brought out the fact that the 

 house-fly was largely responsible for the troubles. 



The habits of this insect are such as to make its presence dangerous. 

 It breeds in filth, and as an adult fly it feeds on all kinds of decaying and 

 fecal matter as well as the sweets and liquids of the dining table. 

 Its feet and proboscis are admirably adapted for carrying those bacterial 

 germs that cause typhoid fever, cholera, dysentery, diarrhoea, tubercu- 

 losis, etc. Moreover, it has been shown that typhoid bacilli swallowed 

 by the house-fly when it feeds on and crawls over contaminated sub- 

 stances survive the passage of the alimentary canal, so that "fly- 

 specks" may contain many active typhoid germs. 



It has been shown that several other species of flies that frequent 

 houses may also convey typhoid bacilli. The "little house-fly" 

 (Fannia canicularis) , the Latrine-fly {Fannia scalaris), the blow-fly 

 (Calliphora erythrocephala) , Muscina siabulans, the cluster-fly (Pol- 

 lenia rudis), and the stable-fly (Stomoxys calcitrans) have all been found 

 guilty and precautions should be taken to guard against their presence. 



The charges proven against the house-fly as an active agent in dis- 

 seminating not only typhoid fever but also cholera, dysentery and tu- 

 berculosis are overwhelming. This insect pest should, therefore, 

 be banished from our midst. If we do not care for our own health 

 we should at least protect the helpless children who are perhaps the 

 greatest sufferers. 



(For further particulars the excellent works of Doctors Hewitt 

 and Howard should be consulted.) 



Anthrax and Infantile Paralysis: 



The stable-fly {Stomoxys calcitrans), the horn-fly (Hcematobia 

 serrata), gad-flies (Tabanus and Chrysops), and the black-fly (Simulium) 

 have both piercing and sucking beaks and are true blood-suckers. As 

 such they are liable to introduce virus into the human blood. Anthrax 

 is a disease of many domesticated animals and of man; and it is 

 believed that these blood-sucking flies are agents of transmission 



