INSECTS AND VEGETABLE PARASITES INJURIOUS TO CROPS 43 Dura has also been found to be the victim of numerous other diseases. Mr. and Mrs. Broun discovered the larvae of a noctuid moth which bores up the stems, and a fungus, Helminthosporium sorghi which, however, only causes the leaves to wilt. One has met with four forms of Smut, (Ustilaginous fungus), a variety of Puccima, and wliat is apparently a bacillary disease—at least a large bacillus was present in a grain head from Sennar, which presented quite a peculiar aspect and showed no sign of insect or fungus infection. Klein, Houston, Potter and others, have drawn attention to the presence and significance of the Schizomycetes in cereals and tubers.

The proper preventive measures for smut and other fungi have been detailed in several reports. The dura in the Dongola district is said to harbour some kind of wire-worm or slug, while that in Sennar is stated to be occasionally eaten by a large species of fly.1 A plant bug or Hemipteron, Aspongopus viduatus (Fabricius), has caused much damage to the melon crop, and specimens of winged adults and wingless larva?

have been preserved and are figured in this Report. (Plate B, a to d.)

In this instance the preventive methods are simple and consist merely in shaking the bugs into pans of paraffin or tar early in the year when they first make their appearance. The gravid females that have wintered are thus destroyed, and so the hosts to which they give rise prevented from appearing. Land that has been infected with these bugs should have all the litter burned in the hibernating season, and all badly infected plants should be pulled up and burned (Theobald).2 These precautionary measures, it seems to me, might very well be adopted and much loss averted.

The ‘ Dura ’ Aphis or ‘ Asal Fly ’ [Aphis sorghi. nov. sp.)

(Plate C.)

By Fred. V. Theobald, M.A.

The following are the structural details of the destructive Dura Aphis which is causing such havoc in the Sudan. The species is new, and I have named it after the plant it attacks. The details are shown on Plate C.

Winged viviparous female.

Expanse of wings 5*0 to 5’5 mm. Length of body 1*5 to 1*8 mm.

Head (Fig. 4) brown, with a pale green line behind across its whole length, with three processes projecting forward, one median and one at the base of each antenna; antenna? brown, the two basal segments green, the third green basally, basal segment Fungus diseases of dura The melon bug and its treatment xThis probably does not refer to a true fly (Dipteron). F. V. T.

2 Second Report on Economic Zoology, p. 117, 1904. F. V. Theobald.