148 CLASS-BOOK OF ZOOLOGY. 



§ 635. The Horse-fly (Oestrus equi) lays her eggs in 

 the shoulders and fore-legs, or on the lips of the horse. 

 In the latter case, being licked off and swallowed, they 

 pass into the animal's stomach, where, principally during 

 the spring, they are found in large numbers, firmly attached 

 by a hook at the anterior extremity of their bodies. In 

 size they resemble a Date. 



\ 636. The Meat-fly, (Musca vomitoria,) a most disgust- 

 ing insect, deposites its eggs, of which it lays about 200, 

 on all kinds of" fresh meat, which it spoils in a short time ; 

 maggots being produced from the eggs in 24 hours. 



\ 637. These maggots grow with such rapidity, that 

 in 24 hours they increase their weight 200 times. They 

 are full grown in eight days, when they let themselves 

 fall on the ground, where they are converted into brown 

 barrel-shaped puppae. 



§ 638. The Cheese-maggots are eaten by many people, 

 in the belief that they originate from the best substance 

 of the cheese ; but that is an error, as these disgusting 

 maggots proceed from the eggs of a small brown Fly, 

 which has very long wings, and is of the size of the 

 common ant. 



QUESTIONS ON SECT. XXXVIH. 



622. What are two-winged Insects? 



623. Describe their larva. 



624. What do you know of the growth and change of their maggots ? 



625. What do many species of Flies resemble? 



626. What injury is done by Flies? 



627. What do you know of the Musquito? 



628. What is the cause of the itching and inflammation produced by 

 its sting ? 



629. What do you know about the eggs of Musquitoes ? 



630. What is said of the larvae and of the increase of Musquitoes ? 



631. When and how was the Hessian-fly brought to America? 



632. Describe it. 



633. What do you know of its eggs, and the destructive power of their 

 maggots ? 



634. What do you know of the Gad-fly? 



635. What do you know of the Horse-fly? 



636. What do you know of the Meat-fly? 



637. What do you know of its maggots ? 



638. What do you know of the Cheese-maggots ? Describe the Cheese* 

 fly. 



