mane, the shoulders, the belly, the 

 neck, and the flanks. Fly takes but 

 a second to attach each egg. Several 

 eggs may be fastened to the same 

 hair; many may be attached to the 

 mane and flanks. 



One female can lay 500 eggs. 



Egg. — Yellow. Ready to hatch 

 in about 7 days. Eggs hatch any 

 time (within 2 or 3 months). The 

 animal licks or bites itself at the 

 spot where eggs are attached; heat 

 and moisture from the animal's 

 mouth stimulate hatching. 



Larva. — Newly hatched larvae 

 are taken into animal's mouth 

 when it licks or bites itself. Larvae 

 burrow into tongue. They continue 

 to burrow for 3 to 4 weeks, then pass 

 into the animal's stomach, attach 

 themselves, and remain until ma- 

 ture. The total period for larval 

 development is 10 to 11 months. 



Mature larvae pass out of animal 

 with feces. 



Throat Bot Fly 



(Gasterophilus nasalis) 



Adult. — Smaller than common 

 bot fly and more rapid in flight. 

 Wings have no markings. 



Female poises in midair, usually 

 near the animal's forelegs, then 

 darts at the animal to attach eggs 

 on hair under the jaws; cements one 

 to four eggs to a hair during each 

 attack, flies away after each attack ; 

 returns in a few minutes. 



One female can lay 500 eggs. 



Egg. — Yellowish. Hatches in 

 about 6 days. Does not require mois- 

 ture or friction for hatching. 



Larva. — Newly hatched larvae 

 crawl into animal's mouth. Usually 



Pupa. — Similar for all three 

 species. The pupal stage begins 

 1 to 4 days after the bots burrow 

 into the ground. The outer skin 

 of the larva hardens to form a 

 protective coating — the pupal 

 case — this case is brown or black. 

 The bot changes into a fly within 

 the pupal case. At the end of the 

 pupal period, which ranges from 

 15 to 70 days, the fly emerges 

 from the pupal case and mates. 

 Another life cycle begins. 



they lodge in the pockets between 

 the molars. 



In 20 to 30 days larvae pass from 

 the mouth into the stomach, then 

 into the forward end of the small 

 intestine, where they attach and re- 

 main until mature. The total period 

 for larval development is 10 to 11 

 months. 



Mature larvae pass out of animal 

 with feces. 



Nose Bot Fly 



(Gasterophilus haemorrhoidalis) 



Adult. — Smallest of bot flies; 

 most rapid in flight. Most hairs on 

 body are dark. Wings have no 

 markings. 



Female darts at the lips of the 

 animal ; deposits one egg at the base 

 of the hair, then darts away. A feAv 

 seconds later she strikes again. Eggs 

 are deposited close to the skin, 

 usually along the front of the upper 

 and lower lips. 



One female can lay 160 eggs. 



Egg. — Black. Hatches in about 2 

 days. Moisture is necessary for 



