174 Relation of G^^ass Insects to Cultivated Crops 



the surface, except in the case of an attack of spring oats in April and 

 May when they were found in the top inch of soil, many actually crawUng 

 out of the soil to attack the stems of young plants above the soil hne. 

 Numerous cases of larvae boring upwards in the stem were observed, 

 the most persistent larvae being those of Agriotes obscurus from 8-12 mm, 

 in length; in conjunction with this attack the various Tipulid larvae 

 were also doing considerable damage. 



The characters of Agriotes larvae as given by Roberts (14) enabled 

 these wireworms to be readily distinguished. Roebuck in the 1918 

 Report of the Intelligence Department, Plant Disease Branch, states 

 that "a downward movement of these larvae to protect themselves from 

 cold was not apparent." This has been verified, the wireworms being 

 taken within 3 inches of the surface on frosty mornings, and, even after 

 continued frost, no migration to lower depths was observed. 



The larvae of Melolontha vulgaris were found chiefly in meadows 

 and waste land, feeding on any available decaying herbage. They showed 

 a distinct preference for lighter soils and were consistently taken in 

 heaps of road scrapings which had been left along roadsides. Here the 

 larvae thrived, the compost of soil, grit, manure and decaying vegetation 

 being evidently most favourable for them. No specific attack was noticed 

 in the locality, though the larvae are reported as attacking mangels in 

 Carnarvonshire in 1917 and potatoes in Norfolk, Surrey and Cardiff in 

 1918, those in Surrey being grown on an old lawn which had been broken 

 up during the winter (i). 



Letna melanopa and Sitones lineatus were frequently found sheltering, 

 the former head foremost in the hollowed portion of the stems of tall 

 oat and cocksfoot grasses, and the latter low down amongst the dry 

 dead leaves of cocksfoot, particularly in the vicinity of a field of "seeds." 

 The attack of Sitones spp. on leguminous crops is very universal and on 

 a field of beans 32 weevils were collected either feeding or resting from 

 62 plants, this was about 11 o'clock on a mid- April morning. Curtis (6) 

 alluding to this ubiquitous weevil in 1844 states, "I well remember that 

 in April and May I could not find a pea-field where the lower leaves of 

 some plants were not eroded, the beans were equally marked." 



The Hymenoptera are represented by only one species which formed 

 galls on couch grass. This insect, which has not been identified, was found 

 only during the winter and spring and I have found no instance of its 

 being taken on any other grass or on any cereal crop. 



The most predominant Lepidopteron was Apamea secalis. The larvae 

 were found feeding internally in the base of the shoots of both grasses 



