58 AN ACCOUNT OF BRITISH FLIES. 
gaster minutus,* Semistellus nigripes, Eurysapus saltatus, Platygaster, 
p.? | 
Four of these Dr. Lindeman found in a collection sent him. 
by Miss Ormerod, viz., S. nigripes, T. Rileyi, M. intermedius, P. 
minutus. There was also a species which agreed with Riley’s 
description of the American Jersius destructor, Say.t But this 
is also found as Ceraphon destructor 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 recommended in districts where the Hessian-fly has been 
at work during the last few years. Invall cases it is found that late- 
sown wheat is more liable to attack than that sown early in the season. 
(«) In the case of autumn wheat, the /aéer 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. 
(8) Agriculturists should also pay great attention to the kind of 
wheat sown, for some resist the attack much better 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 ‘*bere” amongst the barleys. The finer varieties 
are all subject to attack. The thick-strawed varieties do not bend 
* Platygaster, 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 larve of Platygaster devour them. The larve of Platygaster 
undergo the most remarkable changes, they scarcely being recognisable as insect 
larvze ; in many respects the larvz resemble the Crustacean Cyc/ofs in appear- 
ance. Anyone interested in this curious development should read ‘‘ Beitrage zur 
Erkenntniss d. Entwicklungsgeschichted. Insecten.”’ Zezt. f. wiss. 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 Lntomologist, 1887. Parasites of Hessian-Fly.—Miss Ormerod. 
~ ‘* 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. 
