ENTOMOLOGY. 



395 



The grubs are fleshy and (with few exceptions) footless ; - 

 sometimes, hke the Daddy Longlegs grub, they have a hard 

 head, furnished with nippers or jaws ; but often they are cyhn- 

 drical as figured, truncate at the tail, and elongated at the 

 head extremity, which contains a soft mass which answers for 

 a head, commonly bearing a pair of hooks instead of jaws, 

 with which they clear out the substance in which they may 

 be feeding. 



Pupffi various; in most cases the skin of the larva shrinks 

 and hardens, so as to form an oval or cylindrical case in 

 which the change takes place, and out of which Fly-case the 

 Fly makes its way when developed ; but in some instances, as 

 of the Daddy Longlegs, figured p. 394, and some others, is in 

 shape much like the creature within, with its limbs folded. 



The family of the yEstrida^, which includes the well-known 

 Ox Warble Fly, Horse Bot Fly, and the Sheep's Nostril Fly, is 

 parasitic in different parts of animals ; for special details of 

 life-history and means of prevention of the first-named, see 

 publications by Ed. 



2 18 



1, Ux Warblu Fly ; 2, maggot; 3, chrysalis. 



Ostrich Fly (Hippohosca struthionis) and egg-like pupa-case, nat. size and mag. ; 

 foot and claw magnified. 



In the family of the Hippoboscidae, of which some are 

 known as " Forest-flies," the insect passes the larval stage and 



* The maggots of two kinds of Flies {KristdliH and Helophihm) are peculiar 

 for possessing seven pairs of what may be called a kind of claw-like feet. These 

 maggots are known as " rat-tailed larva," from the hinder part of the body 

 being lengthened into a long slender tail-like tube, whereby they can draw in 

 air from above the damp or muddy places in which the maggots lie. 



