84 THE HOUSE FLY DISEASE CARRIER 



able whether it would attack any animal or insect larger 

 than itself. Marlatt states that if pressed with the 

 bare foot or hand, or if caught between sheets in beds, 

 it will unquestionably bite in self-defense. He also 

 shows that the few such cases on record indicate that 

 severe swelling and pain may result from the poisonous 

 injection. Prompt application of ammonia, however, 

 will alleviate the symptoms. 



No one knows much about the life history of this 

 creature. Full-grown specimens are found in houses 

 all through the year; half-grown individuals are some- 

 times found in the summer; the youngest ones known 

 differ from the older ones chiefly in having fewer legs. 

 It is interesting to note that a careful look at the hind 

 segments of the young will show the long posterior 

 legs folded up within and ready to be extended after 

 the next molt. 



Under present conditions of house fly abundance, it 

 might be as well not to disturb this Scutigera when 

 it is found in houses, but with the conditions which 

 will shortly be brought about, we hope, it will be easy 

 to destroy the centipedes with pyrethrum powder, even 

 if they do not, as is likely, die of starvation. 



INSECT ENEMIES OF THE HOUSE FLY 



Predatory enemies. It seems rather strange that, 

 with the very numerous predaceous insects which de- 

 rive their sustenance from soft-bodied and more or less 

 helpless species, there should not be more which gain 

 their livelihood from the larvae of the typhoid fly. It 



