August, '16] PIERCE: HABITS OF POLYDRUSUS 425 



Genus Polydrusus Germar 



This genus was described by Germar in 1817 {Mag. der. Ent., Vol. 2, 

 pp. 339-341) and has for its type, undatus Fabricius, designated by 

 Schonherr in 1826. Schonherr at this time {Cure. Disp. Meth.) 

 emended the name to Polydrosus. LeConte and Horn in 1876 de- 

 scribed the genus Cyphomimus {Proc. Amer. Fhilos. Soc, Vol. 15, p. 

 105) with the type C. dorsalis Horn, which genus in the present con- 

 ception of Polydrusus can only be accepted as a subgenus. The genus 

 belongs to the Family Brachyrhinidse Bedel,. Subfamily Psallidiinse 

 Pierce, Tribe Polydrusini Pierce. In Europe it is subdivided into 

 quite a number of subgenera which may ultimately be raised to generic 

 rank if the habits of the species warrant it. Our American species 

 have not been criticalh^ studied with a view to correlating them with 

 the European classification. 



Four species are apparently native of this country or have been long 

 established. Two species have been recently introduced and one of 

 these is very injurious. 



Polydrusus (Eustolus) impressifrons Gyllenhal 

 Imported Poplar Root Weevil 



This species is found in Europe on willow, especially Salix viminalis 

 L., alder and hazelnut, and its variety Jlavovirefis Gyllenhal is recorded 

 from aspen (Popidus tremvla) and other trees of the genus Populus. 



According to Mr. P. J. Parrott, who is making an exhaustive study 

 of the habits of this weevil in New York: 



The beetle appears during the latter part of May and begins to oviposit immediately. 

 The eggs are white in color and cylindrical in form. They are placed under loose 

 bark, such as appears on the ends of broken branches or on stubs as the result of 

 poor pruning, or in depressions or in wounded branches and trunks covered by 

 projecting bark or even among loose bud scales of dead wood. The eggs are deposited 

 in irregular masses containing from twenty to eighty to an assemblage. Oviposition 

 is most active during June. The newly hatched larvse drop to the ground and 

 subsist on roots. They are known definitely to feed at the roots of willow, poplar 

 and birch. Pupation takes place during early May of the following year. The 

 beetles seem to be partial to wUlow, poplar and birch, but they feed on other plants 

 among which may be listed apple and pear. Applications of arsenicals at first 

 appearance of beetles affords efficient protection against the weevils. 



The adult beetle is covered with beautiful blue-green scales. The 

 legs are reddish. The form is brought out very clearly in Mr. Brad- 

 ford's drawing. 



In order to separate this species from another recent importation the 

 following translation of the original description is given. 



Polydrusus impressifrons Gyllenhal. Schonherr's Gen. et Sp. Cure, Vol. 2, p. 140. 

 Oblong, black, fuscous pubescent, densely clad above and beneath with green 

 scales; antenna; and legs pallid testaceous; rostrum very short; frons impressed; 

 femora mutic; antennal scape reaching behind eyes; funicular joints 3-7 obconical. 



