CHAE^AS GRAMINIS IN SOFTHEEN SCOTLAND. 279 



vene and connect these four different areas hold in the meantime 

 a very much larger stock of C. c/raminis than is normally present, 

 and if the present conditions of vigorous and progressive vitality 

 continue over till another season, there is every reason to antici- 

 pate a plague of caterpillars as widespread and probably as 

 destructive as the voles so lately were. 



As I have already stated, the "hill-grubs" have been familiar 

 to many generations of shepherds, and I have often been told by 

 old men of outbreaks in different parts of the district that hap- 

 pened long ago. And for the most part these outbreaks appear 

 to have been confined to certain localities or farms, and were but 

 rarely general over a wider district in any particular year or 

 years. The years from 1830 to 1836 were, however, remarkable 

 for plagues of the "hill-grub." In these successive seasons the 

 larvfe in question seem to have been spread over most of the 

 southern uplands to a very destructive extent, and only recently 

 I was speaking to an old herd who had seen the sheep-drains 

 "chokeful," so that the water was dammed back by the masses 

 of larva) swept in l)y sudden thunder-showers. The same thing 

 happened this summer, when, after the great thunderstorm 

 on the evening of July 6th last, the drains and ditches on 

 Polgowan farm, at the head of the Scaur water in Penpont 

 parish, were found in many places to have been filled up by the 

 grubs that had been washed in by the extraordinary heavy rain- 

 fall. Mr. Piobert Martin, the tenant of the farm in question, 

 informed me that in several of the hollows of the drains the 

 larvffi were lying to a depth that was measured at 24 inches. 

 Six to twelve inches deep of caterpillars was quite a common 

 feature of this curious phenomenon. On June 18tli a party of 

 anglers fishing down the Ken from the Holm of Dalquhairn to a 

 little past Craigengillan, a distance of several miles, found every 

 trout they captured literally crammed to the mouth with "hill- 

 grubs." Rooks are, as is well known, the great bird enemy of 

 these caterpillars, and since the young broods were strong 

 enough to accompany their parents to the hills, very large flocks 

 of these birds have been in daily attendance on the grub-infected 

 patches on many hillsides. The black-headed gulls {Larus ridi- 

 hundus) and the common gulls (L. canus) are also very fond of 

 these larvpB. Curlews take a good many, golden plovers and 

 lapwings pick them up in numbers, and there is a little bird, 

 the snow bunting, which one could hardly suspect of consuming 

 these larvfe ; yet nevertheless, in a lot of eight snow buntings 

 shot in January some years ago on Crawfordmuir, I found an 

 average of eight or nine undigested skins of C. [prnninis in each 

 of their stomachs. Similarly in some other snow buntings, shot 

 on a Galloway hill in midwinter, I found larvae of Noctua xantho- 

 grajiha, showing, I think, that tliis bird does not always live on 



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