440 PACKARD— ORIGIN OF MARKINGS OF ORGANISMS. [Dec. 2, 



spots. The above was written out at the time, but my later 

 experiment with the rotating wheel (p. 445) quite satisfactorily 

 corroborates my observations. 



Blending of the bars and lines in Deilephila lincata — Early in 

 September I observed at Sugar Hill, N. H., one of these hawk 

 moths flying over and probing the flowers of the sweet william, of 

 which it seemed especially fond, and paying little attention to the 

 candytufts, petunias and marigolds in flower in the same beds. 



During its rapid flight the bars or stripes and lines on its wings 

 certainly blended, rendering the outlines and markings of the wings 

 in their swift motion blurred and very indistinct, with no definite 

 outline. The bars on the outstretched wings are parallel with the 

 transverse bars or rings on the abdomen, the latter being more dis- 

 tinct, as also the longitudinal ones on the back of the thorax. The 

 circumstances then reminded me of the statements regarding the 

 blending of the stripes of the zebra, and the effect was such as to 

 plainly make the moth invisible, or at least much less easily seen 

 and caught by birds. 



I also on the same day observed another of the same species on 

 the other side of the road visiting red clover, etc., and my obser- 

 vations (written as here the same day) were corroborated by a 

 member of my family. 



Blending of the bars in a dragonfly. — On June 27 th of the present 

 year I watched a Libelliila irimaculata flying in my yard. The 

 wings are whitish, with a broad dark brown middle patch, the 

 abdomen being a hoary whitish gray, and very conspicuous. 



During its flight it seemed to me that the colors blended so as to 

 make it more indistinct when more swiftly flying. The observa- 

 tion needs however to be completed, yet this dragon fly is a capital 

 case for further examination. 



17. Abundance of Markings in the Life of Coral Reefs. 



In a lecture delivered at the London Institute on the animal life on 

 a coral reef, Dr. S. J. Hickson said that the richest fauna in the 

 tropics is the region which extends from the growing edge of the 

 reef to a depth of some ten or fifteen fathoms beyond it. And here 

 it is that the struggle for existence is most severe, where the animals 

 are protected and concealed by the most pronounced marks and 

 colors, and provided with stings and spines to defend them in the 

 battles with their enemies. The crowded life appears to be 



