58 



Fig. 50. « The head, antennae, and thorax of this fly are black ; tlic hind 



body is tawny, more or less widely marked with black on each wing, and 

 clothed with fine greyish hairs. The egg-tube of the female is rose- 

 coloured ; the wings are blackish, except at the base, where they are 

 tawny, and very narrow, — they are fringed with short hairs and are 

 ', rounded at the tip ; the legs are pale red or brownish, and the feet are 

 black. The body measures about one-tenth of an inch in length, and 

 the wings expand one-quarter of an inch or more. After death the 

 hind body contracts and becomes almost entirely black." (Harris, 

 Injurious Insects, p. 570.) The antennae of the female are about half 

 the length of the body ; those of the male three-fourths. The former 

 are composed of sixteen oval joints twice as long as thick, and clothed 

 with a number of haii-s ; the latter have short, round joints, each with 

 a chord of rather long hairs. 



After these flies come forth from the pupa state in the spring they speedily, set to work 

 to lay their eggs on the leaves of the spring wheat, now appearing above the surface of the 

 ground, as well as upon that sown the ;iutumn before. From this batch of eggs another brood 

 is soon hatched, the work of destruction goes on, and late in summer the second generation of 

 flies comes forth. The larvae of the summer brood are found almost always under the sheath 

 of the leaf just above the first joint ; their suction of the juices at that point weakens the stalk 

 so much that a high wind very soon bends it down, and even breaks it ofi" when the straw 

 approaches ripeness. (3f course the size and value of the grain is also immensely lessened by 

 the absorption of the sap, which ought to go to filling out the ear. The winter brood attack 

 the young plant lower down, and injure it at the root, frequently killing it outright. 



Having now traced the life of the insect from the laying of the eggs in one autumn to the 

 same point in the following year, we may turn our consideration to the remedies for the foe, 

 which, as in the case of the wheat midge above, may be classified as natural and artificial. 



Natural Remedies. — Though we are, unhappily, so very deficient in natural checks to the 

 spread of the wheat-midge on this side of the Atlantic, our case is very ditFerent .'is regards 

 the Hessian fly. . It is preyed upon and devoured by a number of parasitic insects, whose 

 combined attacks are computed to destroy nine-tenths of every generation of this pernicious 

 foe. Mr. Say described one of the most useful of these parasites under the name of Ceraphron 

 (hsirudor. It is a shining black four winged fly, about one-tenth of an inch in length. " In 

 the month of June, when the maggot of the Hessian fly has taken the form of a flax-.seed, the 

 Ceraphron pierces it through the sheath of the leaf, and lays an egg in the minute hole thus 

 made. From this egg is hatched a little maggot, which devours the pupa of the Hessian fly, 

 and then changes to a chrysalis within the shell of the latter, through which it finally eats its 

 way, after being transformed to a fly. This last change takes place both in the autumn and 

 in the followinu spring. Two more parasites, discovered by Mr. Herrick, also destroy the 

 Hessian fly, while it is in the fltix-seed or pupa state." (Harris.) A fourth has been found 

 by the same observer to attack the eggs of the enemy. " This egg parasite is a species of 

 I'kUygas/tr. It is very abundant in the autumn, when it lays its own eggs, four or five to- 

 "•ether in a single egg of the Hessian Hy. This, it appears, does not prevent the latter from 

 hatching, but the maggot of the Hessian fly is unable to go through its transformations and 

 dies after taking the flax seed form. Meanwhile'its intestine foes are hatched, come to their 

 growth, spin themselves little brownish cocoons within the skin of their victims, and in due 

 time are changed to winged insects, and eat their way out." — Harris. 



It is owing almost entirely to these minute allies that our crops have been preserved to 

 so o-reat an extent, of late years, from the ravages of the Hessian fly. For a time the pest 

 inflicted great damage, but its enemies soon increased and gathered strength, and have suc- 

 ceeded in keeping it within due bounds. Assuredly, we should feel deeply grateful to the 

 merciful Creator, who has provided such effectual, though apparently insignificant, means to 

 save the fruits of our fields from destruction. 



Artijicial lienudlrs. — These are often attempted, but seldom with entirely satisfactory 

 results. The best precaution to take — where the insect has shown it.self in numbers and 

 where the wheat-midge is not apprehended — is to .sow the next crop of fall wheat as late as 

 can be done with safety in the autumn — about the middle or towards the end of September. 



