5 8 AN A ceo UNT OF BRITISH FLIES. 



gaster miniihis,'^ Semistelliis nigripes, Eiirysapus saltatiis, Flafygasfery 

 sp. ? 



Four of these Dr. Lindeman found in a collection sent him 

 by Miss Ormerod, viz., 6". nigripes, T. Rileyi, M. intermedius, P. 

 minutiis. There was also a species vvhich agreed with Riley's 

 description of the American Mersius destructor, Say.f But this 

 is also found as CerapJwn destriidor in Germany, as mentioned in, 

 Kollar and Kaltenbach's works. From this we see that our attack 

 has been derived from some European source, most likely Russia. 



Careful investigations on imported straw on the east coast seem 

 to show that that was not the mode of introduction. It most likely 

 came over in infested screenings, many other diseases and pests 

 being imported in this way in foreign corn.; 



Modes of preventing attack. — The early sowing of wheat and barley 

 is strongly reconmiended in districts where the Hessian-fly has been 

 at work during the last few years. In all cases it is found that late- 

 sown wheat is more liable to attack than that sown early in the season. 



(a) In the case of autumn wheat, the later it is sown the better. 

 In America and Canada, where autumn-sown wheat is started earlier 

 than in Europe, this is a rule especially followed.§ The reason being 

 simply this : that if the wheat is not up until the flies are hatched 

 and dead it cannot suffer from the attack, and for this reason we 

 are free from the attack of autumn wheat, which in America seems 

 to do most of the damage. 



(/3) Agriculturists should also pay great attention to the kind of 

 wheat sown, for some resist the attack much belter than others. The 

 stout-strawed varieties should be chosen. The following are found 

 to resist the attack well : the "golden drop," " Rivett's red," " square 

 head," "chaff red," amongst the wheats; and the "battledore," 

 " awnless," and " here " amongst the barleys. The finer varieties 

 are all subject to attack. The thick-strawed varieties do not bend 



'■' Platygastcr, which is a genus of Hymenopterous insects, lays its eggs within 

 the eggs of the Hessian-fly, and the victims do not live beyond the puparium 

 stage, as the larvai of Platygas/e?- devour them. The larva; of Platygaster 

 undergo the most remarkable changes, they scarcely being recognisable as insect 

 larvje ; in many respects the larvae resemble the Crustacean Cyclops in appear- 

 ance. Anyone interested in this curious development should read " Beitriige zur 

 Erkenntniss d. Entwicklungsgeschichted. Insecten." Zeit. f. iviss. ZooL, Bd. xix., 

 1869. — Ganin. This author (Ganin) has given a very good account of their 

 development. Another account may also be found in Balfour's " Comparative 

 Embryology," 1880, vol. i., p. 345. 



t Entomologist, 1887. Parasites of Hessian-Fly. — Miss Ormerod. 



t " Ergot " is largely imported in this way. 



§ It is recommended in Canada and U.S.A. that wheat should not be sown until 

 after the middle of September. 



