October, ’18] 
BURRILL: NEW CLOVER PESTS 
423 
ing resulted in some cases. Insistent demands of beekeepers that 
these sprays may kill off their bees, are hard to set at rest until a long 
series of toxicity tests in the honey bee has been followed out in line 
with the excellent Federal contributions. 1 
The part which thrips play, the red or black species ( Haplothrips 
statices (Haliday), syn. Phlaeothrips niger Osb. 2 ) in the clover and alfalfa 
seed loss is not understood. In July, 1917, Mr. A. H. Harrison and I 
watched under a hand lens how these species scarify the floret enve¬ 
lopes of clover blooms towards the floret bases. 
Frequent requests for data about mites on clover crowns, also on 
potatoes, dying tree trunks, etc., failed to bring to light any one species 
as primarily to blame, other than that Rhizoglyphus rhizophagus 
Banks 3 4 is most common, some immature gamasids of the Uropodidae 
and Hologamasus inarmatus n. sp. 2 The widespread death of red 
clover crowns after cutting the seed crop infested with aphis, has been 
blamed to Aphis bakeri Cowen, but recent rearings from infested 
crowns in the same area, of numbers of a new species of Sciara (S. 
trifolii Pett. near S. varians 4 indicate other contributory causes. The 
mites befouled other tests as follows: 
Received red clover roots swarming with black-headed, white mag¬ 
gots and white mites, September 30, 1916 from field 4m. NW of Twin 
Falls, Idaho, with a note to the effect that whole fields of clover were 
dying, following the clover aphis epidemic in August and cutting the 
seed crop about September 1. Ewing determined the mite as R. 
rhizophagus and adults from maggot are described above as the Myce- 
tophilid, Sciara trifolii Pett. Under careful watering, the supposed 
dying clover crown was revived so as to send out new sprouts and 
insects were reared as follows: 
October 3, one adult had emerged. 
October 23, 1916, first dozen adults appeared; last one died Novem¬ 
ber 11. 
November 23, 1916, second brood adults appeared; last one died 
November 30. 
December 24, 1916, 5 third brood adults appeared; last one died 
January 8. 
1 N. E. Mclndoo. Sense Organs, etc., Honey Bee. Smiths. Misc. Coll. Publ. 
No. 2381: Mclndoo. Effects of Nicotine as an Insecticide. Jour. Ag. Res., Oct., 1916. 
Cf. C. W. Mally, arsenicals did not hurt bees. Agr. Jour. Union of So. Afr., June, 
1909. 
2 J. D. Hood, det. in letter, Feb. 25, 1918. 
3 H. E. Ewing, det. 
4 Through courtesy of Prof. O. A. Johannsen, described in preceding note by F. 
W. Pettey, Cornell Univ. 
5 Figs. 3 and 4 are made from female of Brood III presumably. 
