Rhynehakt — Life-History and Bionomics of the Flax Flea-Beetle. 505 



effect that "in June, 1915, it was particularly abundant and destructive in 

 Ulster"; and in his latest report (11) he mentions that "this destructive 

 little beetle caused much damage to the flax crop in all three seasons under 

 review"— 1916, 1917, and 1918— and that "in 1917 and 1918 it was found 

 necessary to resow the crop in several localities." It has been estimated that 

 in the year 1917 fully 30 per cent, of the early sown flax in Co. Down was 

 destroyed by flax flea-beetle attacks. 



In the reports of the manurial experiments on flax carried out by the 

 Department of Agriculture, two instances of insect attack are mentioned 

 which, although obscure, may with tolerable certainty be referred to the flax 

 flea-beetle. In the report of the 1909 season experiments (41), when referring 

 to factors affecting the growth of the crop, a statement is made to the effect 

 that " at Ballindrait the brairds were badly eaten by grub " ; and the report 

 for season 1913 (42) states that at ISTewmills centre, " after the brairds 

 suffered injury from an insect attack, the crop grew so irregularly as to render 

 necessary the abandonment of the trials." The latter is obviously a reference 

 to flea-beetle injury ; but, in the first case, the damage may have been caused 

 by "leather-jacket" grubs (TipM/a sp.). During the season of 1919 severe 

 attacks were reported from the flax-growing districts of Co. Cork, and in 

 Ulster the species was abundant, and did appreciable dainage. 



The season of 1921 was remarkable because of the long drought— a con- 

 dition often suggested as most favourable to the ravages of flea-beetles — yet 

 during that season the flax brairds of the different districts in Ireland where 

 the crop is grown were singularly free from attack, and few reports of serious 

 damage have been recorded. 



From Ballinacurra, Co. Cork, a complaint was received that some early 

 sown plots of flax at the Department's plant-breeding station there were 

 being injured by insects, and on examination of the specimens forwarded 

 the species was identified as Zongitarsiis parvulus Payk. The attack was, 

 however, local and chiefly confined to very early sown plots. A similar 

 condition prevailed at the experimental plots in connexion with the field 

 laboratory in Co. Derry. A series of plots sown early in April, and brairding 

 during the last week of that month, were extensively infested, and the young 

 plants suffered considerably. The remainder of the plots were sown during 

 the first week of May, and, brairding twelve days later, were not so 

 attacked, and suffered little appreciable injury, although beetles were present 

 in small numbers, having migrated thence from the earlier sown plots. 

 During the brairding of the flax on the latter the beetles were observed 

 flying to them from all directions ; and it is possible that, as this was the 

 only flax brairding in the immediate district, the beetles swarmed on it as 



