1914 ENTOMOLOGICAL SOCIETY. 85 



In the tropics, where vegetation is most luxuriant, these beetles play an im- 

 portant part in checking the too-lavish growth, but in the Temperate zone where 

 civilized man has brought the earth under cultivation, these twelve tribes, the 

 chosen people of my paper, are nothing better than one of the plagues of Egypt, a 

 most destructive pest, and man's best wits are taxed to prevent an annual loss of 

 many million dollars. 



The Chrysomelians represent a later development than the Cerambycidae or 

 wood-borers, and their adaptation to succulent herbage and the deciduous foliage of 

 flowering plants pari-passu with changes in the vegetable kingdom from sporo- 

 phytes and gymnosperms, presents in its way as wonderful an illustration of adap- 

 tive development as more specific examples such as the symbiosis which has isolated 

 the Yucca and its moth from all creation, till each depends on the other for its 

 very existence and on the other only. 



The larvae of the Chrysomelians are in general soft and helpless; Ceeding 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 he 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 will have to put our l)est foot forward, for it is going to be 

 shank's m'are with us. First we 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 nn the west by an old snake fence and ou 

 the east by a still more ancient stump-fence; the snake fence appears to spring from 

 a bed of oak-fern 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 

 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 

 srrass-blades, some specimens of the Donacia. This is our representative of Tribe 

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

 has only one species, but the Donacia (Eeed beetle, as the Greek name implies) 

 has more than twenty species in ISTorth America. The kind I have found here i.s 

 much like a Longicorn, 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 pov/er 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 aboutt to pupate it encloses itself in 

 an air-tight cocoon which is fastened to the root or stems of the food-plant beneath 

 the surface. The beetle is covered on the under side with a pubescence that acts 

 as a perfect protection, shedding the water like oilskin. The species found here 

 in the cool days of April is more or less cylindrical (convex on the upper side) and 

 quite sluggish in habit, but the Donacia of the dog-days in the height of summer is 



