THE COMMON HOUSE FLY. 



81 



Thus the inside of this broad fleshy expansion is rough like a 

 rasp, and as Newport states, "is easily employed by the insect 

 in scraping or tearing delicate surfaces. It is by means of this 

 curious structure that the busy house fly occasions much mis- 

 chief to the covers of our books, by scraping off the albuminous 

 polish, and leaving tracings of its depredations in the soiled and 

 spotted appearance which it occasions on them. It is by means 

 of these also that it teases us in the heat of summer, when it 

 alight* on the hand or face to sip the perspiration as it exudes 

 from, and is condensed upon, the skin." 



Every one notices that house flies are most abundant around 

 barns in August and September, and it is in the ordure of sta- 

 bles that the early stages of this insect are passed. No one 

 has traced the transformations of 

 this fly in our country, but we copy 

 from Bouche's work on the trans- 

 formations of insects, the rather 

 rude figures of the larva (Fig. 85), 

 and pupa-case (a) of the Musca 

 domestica of Europe, which is sup- 

 posed to be our species. Bouche 

 states that the larva is cylindrical, 

 rounded posteriorly, smooth and shin- 

 ing, fleshy, and yellowish white, and 

 four lines long. The pupa-case, or 

 puparium, is dark reddish-brown, and 

 three lines in length. It remains in 

 the pupa state from eight to fourteen 

 days. In Europe it is preyed upon 

 by minute ichneumon flies (Chalcids). The flesh fly, Musca 

 Ciesar, or the Bine-bottle fly, feeds upon decaying animal mat- 

 ter. Its larva (Fig. 86) is long, cylindrical, the head being 

 pointed, and the body conical, the posterior end being squarely 

 docked. The larva of a Sargus-like form which feeds on offal, 

 transforms into a flattened pupa-case (Fig. 87), provided with 

 long, scattered hairs. The House fly disappears in autumn, at 

 the approach of cold weather, though a few individuals pass 

 through the winter, hibernating in houses, and when the rooms 

 are heated may often be seen flying on the' windows. Other 

 species fly early in March, on warm days, having hibernated 

 under leaves, and the bark of trees, moss, etc. An allied spe- 



S5. Larva ; a, 

 Pupa-cage of 

 House fly. 



Larva of 

 Flesh fly. 



