186 
F. M. CAMPBEL] 
-THE HESSIAN FLY. 
upward between the sbeatb and the now bent stalk. Coining to a 
cleft, it passes into tbe free air, and, partly sustained by tbe straw 
contracting over tbe end of tbe abdomen, and partly by its legs, 
remains in a horizontal position until its thin real pupal membrane 
dries and cracks on tbe upper side of tbe thorax.*' Then, protruding 
its bead and tborax, it frees tbe limbs and body, and appears as a 
perfect insect, to continue its species and die. Tbe preference of 
tbe female, while egg-laying, for leaves leading to tbe second joint 
of tbe plant, would appear to be due to tbe fact, that at tbe period 
her offspring are fully developed, tbe sbeatb which covers them has 
become loose of itself, and offers no obstruction to their release. 
E© 
Fig. 3. (1) Barley plant injured by C. destructor and bent above the joint where 
the larva is situated. (2) Puparia of 0. destructor in situ. The 
sheath of the plant has been removed. „ 
The climate of America induces tbe early sowing of wheat, and 
by September tbe plant is sufficiently advanced to receive tbe eggs 
of tbe second or autumn brood, tbe development of which I have 
just described. Tbe larvae when batched find their way down¬ 
ward to tbe upper part of tbe root, and there they obtain their 
nourishment.! Tbe discoloured blade reveals its injury and soon 
* I have not seen this, but summarize Fitch’s remarks. See ‘Noxious, 
Beneficial, and other Insects’ (1865), p. 139. B. Wagner also describes the 
exit of the perfect insect, op. cit. p. 15. 
t There may even be at this season self-sown barley or shoots from injured 
plants which are as advanced as in late spring, in which case the eggs are laid, as 
by the previous generation, in the leaves above the second joint. 
