hawkins] INSECTS IN THE CO URSE OF STUDY 195 



posterior of the abdomen is near the surface of the water at 

 times when he is starting, the explanation of his rapid move- 

 ments will be obvious. 



The above experiments are mentioned not so much for the 

 valuable information that may come from the working of them 

 out as for the stimulus and means of finding out things for them- 

 selves that may be suggested to the children. A boy eight or 

 nine years old is a natural investigator and needs only to have 

 his lines of investigation started for him. 



In the fifth and sixth years, the work of recognition and life 

 histories should be continued in taking up the economic phases 

 of insect life. Hodge's "Nature Study and Life" has plenty of 

 suggestions for this work. A study of insecticides may well be 

 based on the following points: (i) Chemical constituents; 



(2) The kinds of plants on which it may be or may not be used; 



(3) The feeding habits of the insect pest. 



A PRACTICAL POINT IN THE STUDY OF THE TYPHOID OR FILTH 



FLY 



C. F. HODGE, Clark University 



In dealing with any enemy, insect, fungus, bird or mammal, 

 the first requisite is to learn the whole life story and thus be able 

 to attack at the most vulnerable point. With the mosquitoes, if 

 every household in a town knows the life history and does its 

 part in preventing breeding in stagnant water on the premises, 

 it is really little trouble or expense to do away with the pests 

 entirely. Great progress has been made in the last five years in 

 the control of these annoying and dangerous insects; but every 

 member of a community must do his part. One ignorant or care- 

 less household may bring to naught the best efforts of a whol-- 

 neighborhood. 



The next insect to receive similar attention also belongs to 

 the two-winged flies, the Diptera, and was formerly called the 

 "house fly". Dr. Howard has rechristened it the "typhoid fly" 

 and Dr. Styles, illustrious for his work with the hookworm, offers 

 the appropriate name, "filth fly," for the pest. It breeds in filth, 

 feeds on filth, it carries not only typhoid, but every filth disease, 

 and it smears and specks and covers with filth everything it 

 touches. Filth fly is certainly a name that fits. 



Up to the present our solutions of the filth fly problem have 

 been laborious, expensive, ineffectual and generally disagreeable. 

 Its main feature has consisted in shutting ourselves up in prison. 



