246 ECONOMIC ENTOMOLOGY 



Eggs. — Spindle-shaped, reddish and i to 50 inches long; hatch in 4 

 to 12 days. 



Larva. — A footless maggot, clear-white except for a greenish stripe 

 down the middle; last stage of larva passed in "flax-seed" covering, 

 and having a peculiar "breast-bone," a horny forked structure. 



Pupa. — Pupa case deep rich brown, like small "flax-seeds;" pupa 

 rosy colored and with a pointed beak. 



Broods. — ^Two generations in fall wheat regions, and one in spring 

 wheat regions. Criddle reports a supplementary summer brood in 

 Manitoba, the adults appearing from late June up to middle of August. 

 Pup£e develop which winter over. Webster (640) is of the opinion 

 that the Hessian Fly is two-brooded even in spring wheat sections. 

 Female lays a few, to 50 or more, eggs on upper surface of leaf about 

 last week in August, first week in September or later, according to 

 latitude, altitude and longitude; maggots hatch in about 4 days and 

 move down the leaf to the stem where they embed themselves within 

 the leaf -sheath. In about 3 weeks they change to "flax-seed" but 

 remain as larvae until the following May, when they change to pupae. 

 The flies emerge a few days later to lay their eggs for a new spring brood 

 on the leaves of spring cereals. The maggot stage lasts until the third 

 week in June, and the "flax-seed" stage until the third week in August 

 or later, when the flies emerge (Fig. 156). 



Parasitized by Folygnotus, Merisus, Eupelmus, TetrasHchus, and 

 Entedon, all Chalcids. 



Control. — ^Late seeding in fall on well prepared seed-bed; trap- 

 strips; destruction of all volunteer wheat; destruction of "flax-seeds" 

 at threshing; co-operation. Plowing the wheat stubble deeply immedi- 

 ately after harvest. (See Part IV). 



Clover Seed Midge (Dasyneura leguminicola Lintner).— (Consult 

 Bull. I 34, 111. Agr. Exp. Stn.). A widely distributed pest of red and 

 white clover fields. Alsike, mammoth and alfalfa are uninjured. 



Adult. — A minute 2 -winged fly,K2 inch long, with red abdomen and 

 long reddish-brown legs and antennae; head and thorax black; wings 

 transparent with dusky hairs. April-May and July-August. 



Eggs. — Very minute, orange, smooth and transparent. Laid in 

 green flower-heads, hatch in about a week. 



Larva. — A footless orange maggot, Hq mch long, and with nine pairs 

 of respiratory tubercles and a sternal spatula. 



