82 



[Hemichionctspis aspidistme], Bephrata cubensis, and hemispherical 

 scale [Saissetia hemisphaerica] on sour sop, Chaelopsis debilis, Lw., 

 Hippelates pallidus, Lw., Lonchaea polita, Say, long- tailed mealy-bug 

 [Pseudococcus ndonidjwi], and soft scale on beet, mango fruit- fly 

 [Daciis ferruginens] on guava, purple scale [Lepidosaphes becJcii] on 

 citrus, and Tyroglyphids on cassava from Cuba ; a Cerambycid beetle 

 on citrus from Jamaica ; and purple scale [Lepidosaphes beckii] on 

 citrus from Honduras. 



Miller (D.). Control of New-Zealand-Flax Grubs. Investigations into 

 Parasites. — Neiv Zealand J I. Agric, Wellington, xv, no. 6. 20th 

 December 1917, pp. 303-306, 6 figs. 



A small Ichneumonid has been found paLasitising the young larvae 

 of Xantliorhoe praefectata (New Zealand flax-grub) to the extent of 

 30 per cent, in the fiax-growing district south of the Shannon-Foxton 

 line, the flax there being comparatively free from the attacks of the 

 grub, while in the swamp district north of that line no parasitised 

 larvae have been found. The mature parasites emerge simultaneously 

 with the hatching of the first spring brood of larvae. Another larger 

 Ichneumonid occasionally attacks the larvae of X. praefectnta : but 

 unlike the former it pupates in the pupae and not in the larvae of the 

 host. Tills species, however, does not seem to confine itself to 

 X. praefectata sufficiently to exert much control. 



Another flax-grub, Melanckra steropastis, which attacks the edge 

 of the leaf and not the lower surface, is attacked by a fly, Phorocera 

 marginala, which, however, also parasitises several other species of 

 insect larvae. 



Miller (D.). The New Zealand Flax-grub. Progress of the Investiga- 

 tion. — New Zealand JL Agric., Wellington, xvii, no. 4, 21st October 

 1918, pp. 209-215, 2 figs. 



This paper supplements previous ones alieady noticed [see this 

 lieview, [Ser. A, v, p. 453 and 525] in suggesting artificial methods 

 of controlling XantJiorJioe praefectata (New Zealand flax-moth). The 

 most effective results by utilising excessive moisture are to be obtained 

 at the time when the insect is pupating in the ground, since humidity 

 is fatal to it just at the stage when pupal transformation occurs. 

 The existence of more than one generation, however, places a difficulty 

 in the way of this method, since the periods of pupation and larval 

 activity overlap. There are, however, brief periods when, for the most 

 part, both generations are pupating simultaneously, and wlien flooding 

 should be most effective. Such periods are: — (1) from the latter 

 part of July to the end of September, which would affect the pupae 

 of the overlapping generation due to emerge in August and also those 

 of the main generation pupating in August and Spetember ; (2) from 

 December to February, affecting the second brood of the overlapping 

 generation pupating during December, and that of the main generation 

 pupating during February. The use of excessive moisture as a means 

 of control would involve the sinking of artesian wells and the cutting 

 of a network of open drains, work that entails considerable cost both 

 in initial outlay and upkeep. 



