168 ZOOLOGY. 



full size, leave the plants, and creep into the soil, 

 where, in the following spring, they become pupfe, from 

 which flies emerge fourteen days later. There are, 

 therefore, two generations annually. The spreading 

 of Hessian flies into regions where they were formerly 

 unknown may be caused by (a) straw containing the 

 linseed-like pupae (straw for paper manufacture, 

 packing, etc.); (6) grain, among which are often 

 i'ound pupae that have fallen out of the haulms among 

 the separated grain. Remedies: 1. Sowing the 

 winter grain as late as possible, so that the females 

 of the summer generation when they come out of the 

 pupse will find no winter-grain plants in which to 

 lay their eggs. 2. Ploughing up the stubble immedi- 

 ately after harvest, or else burning it, so that the 

 pupae found above the lower nodes are either deeply 

 buried or else burnt. 



The Scarlet Wheat Midge (Cecidomyia equestris). 



Female about | inch, male ^ inch ; cherry red, 

 with yellow hairs; back of the thorax dark brown. 

 Antennae as long as the body in the male, half as long 

 in the female. On the wing from May till June; 

 lays its eggs on the leaves of grain plants, at the 

 base of the uppermost leaf by preference. The 

 blood-red maggots, when they are hatched, let them- 

 selves slide down, and get between the leaf-sheath 

 and haulm. Here they work themselves into the 

 haulm, making a longitudinal groove, the walls of 

 which swell more or less, and the end of which is indi- 

 cated by an obvious transverse thickening. The leaf- 

 sheath hiding the attacked part of the stem is usually 

 more or less swollen. These gall-like outgrowths 

 take up a great deal of nutritious matter, not only 

 from the affected haulm but also from the plant at 

 large, so that the regions not directly attacked are 

 retarded in their growth. The larvae are full grown 



