DESCRIPTION OF THE PLATE. 



Fig, 1. ^grilus ruficollis. -^ab. 



" a. Naturallength. 

 Fig. 2. Hessian fly, male. (Cecidomyia destrttctor, t^ .) 



" b. Its natural size. 



" c. Ventral view of the terminal segments of its abdomen. 



" d. Its antennae. 

 Fig. 3. Hessian fly, female. (C destructor, p.) 



'* e. Its antennae. 



" f. Profile view of the head, palpi, and origin of the antennae. 



" g. Dorsal view of the worm or active larva. 



" h. do do " flax seed," or larva case. 



" i. Ventral view of the same. 



" j. Lateral view of the same. 



" k. Dorsal view of the lormant larva, dissected from the larva case. 



" 1. Ventral view of the pupa. 



" m. Wheat stalk; sheath broken away, showing the young worms on 

 their way to the joint. 



" n and o. Wheat stalks; sheath broken away, showing the "flax 

 seeds " in their ordinary situation. 



A. Appearance of a healthy, (*) and a diseased (t) shoot of wheat in au^ 



tumn, the worms lying at §. 



B. Appearances of a healthy (**) and two diseased stalks of wheat at har- 



vest time, (tt) Stalk broken, from being weakened by the 

 worms. §§ Base of sheath swollen from worms having laid 

 under it, and perforated by parasites coming from those worms. 

 All the illustrations are magnified, except m and those following it. 



