October, '17] scientific notes 503 



Besides the above, the C. F. Baker collection with approximately 30,000 specimens 

 is on deposit and available for study. 



During the past six months over 60 series of specimens, many including 25 or more 

 species, from collectors and economic workers, have been determined. This work will 

 be continued zealously and determinations made and returned as quickly as is con- 

 sistent with accuracy. 



Edmund H. Gibson, 

 In Monthly Letter of the Bureau of Entomology. 



Notes on Tarsonemus pallidus Banks (Acarina).' The pest, Tarsonemus pallidum 

 Banks, although common in greenhouses on such plants as geranium, cyclamen, 

 snap-dragon, etc., has not been studied sufficiently to afford life-history data upon 

 which to base control measures. 



The mite lays eggs on the under surface of the leaves either singly or in groups. 

 The eggs hatch in 3 to 7 days at a temperature of 25°C. and the larva which is minute 

 and pearly white passes through two stages, an active and a quiescent period. The 

 active period averages 2.2 days and the quiescent, 1.7 days, the temperature ranging 

 between 20 and 25°C. The skin is moulted at the end of the quiescent period and the 

 adult mite emerges. The total length of the life cycle from egg to adult averages 

 9.1 days. The adults begin to lay within two days after emergence and the eggs 

 whether fertihzed or not produce normal larvae usually of the female sex. The in- 

 sect is parthenogenetic and continuous generations of isolated females have been 

 kept for 5 months without the intervention of the male. The eggs are laid at the rate 

 of 1 or 2 per day and adults kept in confinement sometimes Uve as long as 17 days. 

 The total egg-laying capacity is from 12 to 17 eggs per female. FertiUzation appar- 

 ently takes place while the female is still quiescent, but copulation has also been 

 seen to take place between adults of both sexes. The ratio of males to females 

 under normal conditions is about 1 to 8. 



Experiments indicate that in winter httle trouble should be experienced from the 

 attacks of the mite if plants are kept well spaced and reasonably dry. In summer it 

 is best to syringe daily until control is obtained with a stream of not less than fifty 

 pounds pressure. The mites are more easily dislodged than the red-spider and con- 

 trol methods offered for the latter mite by Ewing- are therefore effective in com- 

 bating the Tarsonemus mite. 



The writer suggests the name "paUid mite"' as a common name rather than "cycla- 

 men mite" as used by Moznette,^ because of the fact that it occurs on other plants as 

 well as cyclamen and often causes as much or more injury than to cyclamen. 



Philip Garman. 



The Reddish-brown Plum Aphis in New York State. In reference to the paper 

 by W. M. Davidson on p. 350, vol. 10, of the Journal, the following information 

 may be of interest. In 1897, Lintner, 13th Rept., p. 363, recorded the presence of a 

 species infesting the plum. Specimens were sent to Washington and were studied 

 by Mr. Pergande, but were not determined specifically. Pergande's note is as 

 follows: "June 21, 1897. Received from J. A. Lintner, Albany, N. Y., a few specimens 

 of a Rhopalosiphum found at East Greenbush, Rensselaer Co., opposite Albany, on a 



1 Contribution from the Entomological Department, Maryland Agricultural Ex- 

 periment Station. 



2 Ewing, H. E. Oregon Agr. College Exp. Station. Bui. 121: 87, 1914. 



3 Garman, P. MarjMand Agr. Exp. Station. Bui. 208, 1917. 

 *Moznette, G. F. Jour. Econ. Ent. 10: 344, 1917. 



