Makch 27, 1908] 



SCIENCE 



505 



island stations. This accounts in part for the 

 failure of Mr. Newcomb to find decisive in- 

 dications of eosmical temperature influence in 

 his recent study of temperature. Further- 

 more, coast and island stations do not respond 

 simultaneously or always in the same direc- 

 tion to changes of solar radiation, as is shown 

 by a comparison of monthly changes at sta- 

 tions in latitude 5° N. with the monthly 

 changes of insolation. This consideration ac- 

 counts still further for Mr. Newcomb's failure 

 to find evidence of eosmical temperature in- 

 fluence. 



The disagreement of Mr. Langley's often 

 quoted value, 3.0 calories, for the " solar-con- 

 stant," with that here adopted (2.1 calories) 

 is due entirely to a supposed failure of the 

 exponential transmission formiila for homo- 

 geneous radiation. There is no sound evi- 

 dence of such failure, and therefore we must 

 accept Mr. Langley's direct results of 2.06 at 

 Lone Pine, or 2.22 at Mountain Camp, or still 

 better their mean 2.14, as his value of the 

 " solar constant." Thus the method of homo- 

 geneous rays as employed at sea level (Wash- 

 ington), at 940 meters (Lone Pine), at 1,800 

 meters (Mt. Wilson), at 3,500 meters (Mount 

 Whitney) yields values of the solar constant 

 agreeing within the limits of accuracy of the 

 observations and of the real variability of the 



E. L. Paris, 

 Secretary 



THE BIOLOGICAL SOCIETY OF WASHINGTON 



The 439th meeting was held February 8, 

 1908, President Stejneger in the chair. 



Dr. L. 0. Howard gave a lantern slide lec- 

 ture on " Some New Parasitic Work." 

 He mentioned some recent observations on 

 parasites imported from Europe for the pur- 

 pose of destroying Porthetria dispar and 

 Ewproctis chrysorrhcea in New England, de- 

 tailing especially the interesting habits of 

 Pteromalus egregius Forst., and the success 

 which has been achieved in forcing extra 

 generations in the laboratory in the winter. 

 He also spoke particularly of the Tricho- 

 gramma and Telenomus egg-parasites of 

 chrysorrhcea and the methods used in breeding 



these forms artificially. He further spoke of 

 new and important work being carried on by 

 his assistants in Texas and Louisiana in 

 breeding native parasites of the cotton boll 

 weevil; and also of the biology of Lysiphlehus 

 triticij an abundant parasite of the Toxoptera 

 graminum. He announced that the Lysiphle- 

 hus has recently been discovered to be 

 parthenogenetic. Some recent work by F. M. 

 Webster, of the Bureau of Entomology, U. S. 

 Department of Agriculture, and his assistants, 

 with the parasites of Ceddomyia destructor 

 was described. The principal parasite, Poly- 

 gnotus hiemalis Forbes, has been found to be 

 polyembryonic, and a Tetranychus has been 

 found to be hyperparasitic in the cells of the 

 Polygnoius. The paper was introduced by 

 some general considerations in regard to 

 parasitism with insects. 



In reply to a question Dr. Howard said that 

 the campaign against the gypsy moth had 

 thus far produced no visible effect on the 

 abundance of the species, but immediate suc- 

 cess was not predicted. While the state of 

 Massachusetts may be impatient of results, 

 they may be four or five, or even ten years in 

 coming and of course may possibly never come 

 at all. He is hopeful, however, that among 

 the forty to fifty species of its parasites means 

 will be found to hold the moth in check, 

 though American parasites of these parasites 

 may enter into the problem. 



The next paper, entitled " List of Plants for 

 Aquatic Gardens," was by Mr. H. W. Clark, 

 and was illustrated with lantern slides. 



In looking through the literature at hand 

 on water gardens, a number of desirable 

 aquatic and marsh plants were found un- 

 mentioned. Among the charads, several 

 species are very attractive, their symmetrical 

 forms, dainty green colors and bright red 

 fruits adding much to the beauty of the pond- 

 bottom. Chara rohhinsii is a delicate densely 

 branched form growing in shallow water or 

 at the water's edge, sometimes partly exposed. 

 Chara foUolosa is a robust but very sym- 

 metrical form. There are several other charas 

 equally desirable. Nitella hatrachosperma is 

 a minute but beautiful plant, the branches be- 



