118 Bulletin of the Brooklyn Entomological Society Vol. XV 



BOOK NOTES. 



Inbreeding and Outbreeding, by Edwin M. East, Ph.D., and 

 Donald F. Jones, Sc.D. (Monographs on Experimental Biol- 

 ogy, J. B. Lippincott Co., $2.50.) 



This is the fourth to be published of these monographs. While 

 it cannot, in its very nature, be exhaustive, this volume gives an 

 adequate account of its subject. It applies the discovered facts 

 to the future of the human race. The non-technical reader will 

 find in this work an interesting and connected account of much 

 highly technical matter, frequently too abstruse for any except 

 the highly specialized geneticists. The first ten chapters lead up 

 to the last three, which develop and apply the practice of in- 

 breeding and outbreeding to plant and animal improvement, and 

 indicate their effect on individual men and on the race as a whole. 

 As a part of the general literature of the theory of evolution, or 

 tiansfoimism, this work developes one of its phases in relation 

 to ourselves as a race, as individuals and as progenitors. 



Some Habitat Responses of the Large Water-Strider, Gerris 



remigis Say. C. F. Curtis Riley. (Am. Nat., LIII : 394- 



414, 483-505, 1919; LIV: 68-83, 1920.) 



This is one of those time-consuming yet necessary pieces of 

 work, whose results, in the very nature of things, must lack the 

 clean-cut finality of an euclidean demonstration. 



Dr. Riley has painstakingly and systematically worked out the 

 responses of water-striders in their natural habitat, his work lap- 

 ping over three years. The net result is that water-striders 

 always endeavor to reach water. If the water is perceptible to 

 their senses, which it appears to be up to 12 feet distant, the in- 

 sects orient themselves and easily reach it irrespective of the 

 direction in which the water Hes from them. Beyond that dis- 

 tance, they resort to trial and error, like any other animal. He 

 has thus shown that which other observers have known in a 

 sketchy, general way. He has also shown, as a by-product, that 

 there is some measure of thought and actual volition involved in 

 these responses, which can scarcely be interpreted as a mere 

 tropistic reaction to external stimuli. This last is borne out by 

 the fact that under certain conditions the sense of sight came 

 into play, while under others some perception of moisture seemed 

 to give the direction. 



Such work as this, while tedious in comparison to the positive 

 discoveries made, must be done if we are to have facts to work 

 on. The aquatic Hemiptera offer great opportunity for such 

 controlled experimentation under natural conditions. 



J. R. T. B. 



