364 JOURNAL OP ECONOMIC ENTOMOLOGY [Vol. 1 



Aphis bakeri Coweu 

 Some of the More Important Literature 



Aphis halcerV Cowen, Bull. 31, Tech. Ser., Colo. Ex. St., p. 118, 1895. 

 Aphis cephaUcola Coweu, ibid., p. 118. 



Aphis hakeri, Huuter, Aphid. N. A., Bull. 60, la. Ex. St., pp. 93, 132, 1901. 

 Aphis cephaUcola, Huuter, ihid., pp. 95, 132. 



Aphis hakeri, Sanboru, Ks. Univ. Scl. Bull., Vol. Ill, No. 8, pp. 251, 255, 

 1906. 

 Aphis cephaUcola, Sanborn, ihid., pp. 251, 256. 

 Aphis hakeri, Gillette & Taylor, Bull. 133, Colo. Ex. St., p. 28, 1908. 



Mr. Cowen collected this louse from stems of red clover (Trifolium 

 pratense), and from the heads of white clover {T. repens). During 

 the past three years we have taken this louse many times in the vicin- 

 ity of Fort Collins, Denver, Delta, Paonia, Montrose, Grand Junction 

 and Rocky Ford, Colorado. It occurs early and late in the season in 

 greatest numbers upon the stems of red clover close to the ground, 

 where, in mild seasons at least, it doubtless spends the winter as vivipa- 

 rous females and young. It has lived and done well all winter upon 

 clover plants brought into the laboratory by Mr. Bragg. 



As I have succeeded, with the aid of good observers, in working out 

 the life history of this louse quite fully, a list of our written records 

 for Colorado might be worth printing. The additional observations 

 that we have made, but which have not been written down, far exceed 

 the written records which follow in chronological order, disregarding 

 the year : 



March 22, '07, Fort Collins, apterous and alate females and alate 

 males, on red clover (insectary). — Bragg. 



April 2, '08, Fort Collins, apterous females on Bursa B. -pastor is. — 

 Bragg. 



April 11, '08, Eckert, stem-mothers, young to fully grown, also some 

 3d generation lice half grown on pear buds. — Gillette. 



April 13, '08, Delta, stem-mothers, small to fully grown, many exam- 

 ples on pear and apple buds. — Gillette and Weldon. 



April 26, '08, Fort Collins, alate and apterous females, on apple (in- 

 sectary) . — Gillette. 



May 9, '07, Fort Collins, apterous and alate females, on sweet clover. 

 —Gillette. 



jMay 15, '07, Fort Colli??s, alate and apterous females on red clover. — 

 ^ Gillette. 



'It is not improbable that Oestlun(r.s .1. trifolii was an immature apterous 

 example of this species, but trifolii was given as a root louse, which bakeri is 

 not; neither is it pulverulent, and the more statement that it was a pink 

 louse, quite similar in other respects to A. niiddleloni. does not seem to be a 

 characterization sufficient to identify it. 



