26o ECONOMIC ENTOMOLOGY 



Sheep Bot Fly {(Estriis ovis Linn.). Adult. — A dull-yellow fly a little 

 larger than the House-fly and covered with minute spots; abdomen 

 with five rings, velvety and variegated with dark-brown and straw 

 color. Antennae small ; eyes purplish-brown ; ocelli three on top of head ; 

 no mouth; wings transparent extending beyond body ;alulets large cover- 

 ing the poisers. June-August. 



Eggs. — Deposited in nostrils of sheep; hatch almost at once. 



Larva. — Maggot works its way up the nasal passages until it reaches 

 the frontal sinuses, the cavities between and above the eyes. There 

 it attaches itself and feeds on the mucus present. Young is creamy- 

 white, with two brown spots, spiracles on last segment; full grown mag- 

 got darker, particularly posteriorly; two small hooks on head; small 

 rounded spots on sides of each segment. When mature, maggot passes 

 down the nasal passages and falls to the ground, which it enters 

 to pupate. 



Pupa. — Puparium smooth, hard, and black, tapering toward 

 head; duration 40-50 days. 



Control. — Apply tar to the nose; furnish a shed for the sheep or a 

 plot of plowed or dusty ground. 



DROSOPHILID.S (POMACE FLIES) 



Pomace Fly {Drosophila ampelophila Loew.). — This small fly breeds 

 in decaying or over-ripe fruit, and is a common pest about fruit-stores. 

 It is also suspected of being a typhoid-transmitter. The adult is a 

 small light-brown fly with bright-red eyes; the maggot is white and 

 about }'4 inch long; the pupa is yellow or brown with two long horn- 

 like breathing tubes at anterior end. The front tarsus of the male 

 has a comb of black spines on its upper side near the tip. 



OSClNIDiE (GRASS STEM MAGGOTS) 



Wheat Stem Maggot (Meromyza americana Fitch).^ — (Consult Bull. 

 42, Bur. Ent., U. S. Dep. Ag.) Adult. — A slender fly; yellowish-green, 

 I5 inch long, with 3 dark stripes running down the back; femora of 

 last pair of legs abnormally developed; eyes golden-green (Fig. 166). 



Eggs. — About 1-^0 inch long, and glistening white. 



Larva. — A watery-green footless maggot, }4, inch long, tapering to- 

 ward front end and broader posteriorly. 



