DIPTERA OF MINNESOTA. 



81 



in privies; two others in decaying wood and in moss respectively. 

 Many, however, both in the larval and pupal stages occur in water, 

 some even being found in water that is salty or alkaline. Some have 

 even been discovered in a hot spring in Wyoming, where the water was 

 so warm as to render it impossible to keep one's hand in it. We figure 

 the larva of one species in two positions, to show the method of locomo- 

 tion in water, and also the coronet of filaments at the posterior end 



Fig. 71. Stratiomyia discalis. Lugger. 



of the body, which is in part at least, of use in respiration, in that it 

 can include in its mesh a bubble of air, and take this bubble below the 

 surface. The larva figured can creep on earth, or on mud. Limbs 



are not present. One larval form, 

 Hermctia ilhicens, has been found in 

 the intestine of man, and has also been 

 bred in Irish potatoes. Doubtless its 

 occurrence in the human intestine is 

 due to the eating of uncooked vegeta- 

 bles, such as lettuce, upon which the 

 larva may be living. Maggots of this 

 form are also found in catsup exposed 

 to the air, and their occurence in bar- 

 rels of catsup has been explained on 

 Fig 72 A stratiomyid larva, on left, the grouud that the fcmalcs lay their 

 Se?ifrvr1rscendi,rg!''Sn''r'iX! ^ggs iu the material oozing through 

 larva within pupal skin. After Swam- ^j^^^ cracks in the barrel, and the small 



merdain. 



