34 Descriptive Zoology. 



The legless larva is called a maggot. After living in this 

 state about a week, it becomes a pupa, remaining in its old 

 larval skin, which is called a puparium. (See Fig. 27.) In 

 a week more it emerges as a fly. There may be, therefore, 

 ten or a dozen generations in a single summer. A small 

 number live over winter, hiding in crevices in walls and 

 similar places. House flies are worse than mere nuisances, 

 they are spreaders of disease. On the other hand they 

 do much good as scavengers. 



How Flies Crawl. The fly has many little hairlike pro- 

 jections on its feet. These secrete a sticky substance from 

 their ends, by means of which the fly adheres to smooth 

 walls and ceilings. 



Other Kinds of Flies. The stable flies closely resemble the house 

 flies, but have a sharp, piercing sucking tube. They sometimes rind 

 their way into houses, especially on warm, rainy days in the fall. On 



the other hand many of the flies 

 seen about stables are house flies. 

 The horseflies are well known, 

 the most common being known as 

 the "greenhead"; a still larger 

 form is dull black, and in the West 

 is called " bulldog, 11 from its size 

 and persistency ; still smaller than 

 either are those with banded wings, 

 and these usually have the wings 

 spread wider so that the fly looks 



FIG. 28. THE BEE KILLER. triangular; some of these are called 



u deer flies. 11 It is a surprise to find 



r rom Hyatt s Insecta. 



the big black horseflies abundant 



and annoying in the cold air of the high tops of the Rocky Mountains. 

 Among the forms that annoy man and beast are the black flies, or 

 midges, often swarming in the Adirondacks. On account of their 

 smallness the Indians call them " no-see-ems. 11 To guard himself 

 against these pests the hunter and the fisher often anoint the face 

 and the hands with a mixture of tar and oil of pennyroyal. 



