388 THE CANADIAN ENTOMOLOGIST. 



The larvcc of the Chrysomeh'ans are in general soft and help- 

 less; feeding, as they do, in the open and gregariously, they are 

 easily destroyed; but several factors contribute to their notable 

 success in the struggle for existence: their immense numbers, the 

 rapidity of their growth (which enables them to produce more 

 than one brood in a season), and the ability of the mature insect, 

 in most cases, to hibernate. 



A few of them retain traces of an earlier condition in being 

 stem-borers, or in tapping the roots of plants, as the Donacias; 

 and it may be a sort of atavism that impels Cryptocephalus and 

 Glyptoscelis to resort to the needles and bark of white pine. 



Our train is now slowing down to let us off at Quay's Crossing, 

 and for the rest of the day we'll have to put our best foot forward, 

 for it is going to be Shank's mare with us. First wc go a quarter 

 of a mile east to Mose Robinson's mill-pond and Pine Grove 

 School-house. Just after crossing the stream here we turn south 

 down a grassy lane, flanked on the west by an old snake fence and 

 on the east by a still more ancient stump-fence; the snake fence 

 appears to spring from a bed of fern-oak and brittle bladder. The 

 lane is filled with sweet-briar and the stump fence festooned with 

 wild grape-vine; a fortnight ago the briar and the grape-vine were 

 both in bloom and the lane was redolent with two of the most 

 delicious scents on earth. A little way on, at the foot of a sandy 

 slope, we cross a tiny brook of lovely, cool spring water, its surface 

 mantled with water-cress. Here in the early season, as early as 

 April, are nearly always to be found about the grass-blades, some 

 specimens of the Donacia. This is our representative of Tribe I, 

 a small tribe generically, consisting of two members only; the 

 genus Hffimonia has only one species, but the Donacia (Reed- 

 beetle, as the Greek name implies) has more than 20 species in 

 North America. The kind I have found here is much like a Longi- 

 corn, and in early days was mistaken by me for a member of that 

 family; it differs from the Chrysomelians in being long and narrow 

 in shape, usually yellowish brown in colour and of a metallic lustre. 

 The larva feeds about the roots and bases of aquatic plants and 

 has acquired the power of living under water by tapping the air- 

 vessels of its food-plant. It has actually a small process on the 

 body which it uses as a probe. When about to pupate, it encloses 



