EDITORIAL 267 



Apodcmus. The pressure upon our space prevents further 

 indication of what may be found in Part XVI. of this 

 exhaustive monograph, the contents of which are on the 

 same high level of accuracy and completeness as in the 

 previous numbers. 



The study of insects from the all-important economic 

 point of view proceeds apace. An article by R. A. Wardle, 

 on the life-histories of two parasites, one Hymenopterous 

 and the other Dipterous, 1 is of much importance to the 

 cultivator of the Larch, inasmuch as the insects in question 

 prey upon a Sawfly which is extremely destructive to this 

 tree. The paper gives in the first place a useful list of 

 the known parasites of the Sawfly, which, by the way, is 

 known as Nematus eridisonii. Then follow an account of 

 the results obtained from rearing the Ichneumonid parasite, 

 Mesoleius tenthredinis, and a full account of the structure 

 and life-history of Hypamblys albopictus, a second parasite of 

 the same family. The Dipterous parasite is Zenillia 

 (Myxexoristd) pexops, and since this is new to the British 

 list, it also is described in full detail. An important question 

 raised in this paper is that, since the Dipteron appears to 

 predominate at the expense of the Hymenopteron, future 

 work should be aimed at a study of the respective values 

 which these parasites bear in the control of the Sawfly. 



A note by J. C. F. Fryer, on " An Insect Harmful to Newly- 

 budded Rose, Apple, and Plum," 2 is of considerable interest. 

 The insect in question is a member of the Cecidomyiidai, or 

 Gall-midge family, by name Clinodiplosis oculiperda. The 

 maggot of this fly has caused numerous failures in stocks 

 during the last two years, but only as yet in the southern 

 English counties. Let us hope that the spread of this pest 

 may soon be checked. As a preventive measure it is recom- 

 mended that the raphia fibre used in tying up the buds be 

 replaced by woollen thread which has been soaked in a 

 mixture of turpentine, linseed oil, and naphthalene, the 

 threads being dried off before using. Gall-midges in general 

 are of much economic importance, for the family includes 



1 Jonrn. Economic Biology, October 1914, PP- 85-104, plates iv.-vi. 



2 Journ. Board of Agriculture, October 1914, pp. 636-637. 



