20 THE ERRATIC ARMY- WORM. 



have. In studying the road traveled by the armies of such 

 worms we can usually detect where the majority of them were 

 born, and find, as a verA^ generalrulc, that this is an old straw- 

 stack. It seems to have wonderful attractions for this in- 

 sect, and this being the case the removal or disposal of these 

 useless or unsightly objects is an excellent method to prevent 

 an undue increase of army-worms. The illustration shows 

 the adult insect, a pupa in its underground cell, and a larva 

 in the act of eating off the chaff from an ear of wheat. 



THE ERRA.TIC ARAIY-WORM. 



( Xoctua fennica Tausch ) . 



As has been stated betorc, almost any species of cut- 

 worm, favored by exceptionally good conditions, may be- 

 come a veritable army-worm. Early last spring reports 

 reached this office that the country about Hinkley \vas in- 

 vaded by immense numbers of caterpillars which devoured 

 every green thing upon the face of the ground. At the invi- 

 tation of a gentleman from that place, and also prompted 

 by curiosity to see this new army-worm, the entomologist 

 paid a visit to the invaded region and studied the worms. 

 The great majority of these caterpillars which are shown in 

 fig. 12 on plate III, had already disappeared and only com- 

 paratively few were still found running about in search of 

 food (fig. 13, plate IV). The'caterpillars are velvety black with 

 a number of longitudinal yellowish lines and have a brownish 

 head. The presence of these worms was painfully evident 

 as they had devoured ever3'thing in the nature of a leaf, and 

 had, prompted by hunger, even eaten the 3^oung bark of such 

 plants as poplars, willows, cherry, sumach and others (fig. 

 14-, plate lY). All the foliage of the plants that had found a 

 home in this region since the great fire in 1893 seemed to be 

 to the taste of these worms. They preferred, however, such 

 plants that are bitter, hence the foliage of cherries, poplars, 

 willows and sumachs was the first to be eaten; after these 

 plants had been denuded nearly all others were devoured 

 and only certain grasses fared better. Owing to the rainj^ 

 spell numerous pools of water had been formed in which, 

 like islands, were some young trees, but even these had been 



