Pomona College Journal op Entomology 859 



OBSERVATIONS ON THE ECOLOGY OP DRAGON-FLY NYMPHS: 

 REACTIONS TO LIGHT AND (JONTACT 



C. p. RILEY 



Ann. Eiit. Soc Am. Vol. V, No. :5, 1912. 



In their natural habitat they respond strongly to contact. They respond 

 ncfratively to stron<i lifilit; this is a |)hotia response and not a reaction to tem- 

 perature. They also exliil)it a "clasping response," seizing each other around 

 the thorax and abdomen by means of their thoracic appendages. Sometimes 

 as many as fifty individuals are clasped together in this way. The response 

 of these nymphs to photic stiuuili may be overcome by response contact. It 

 seems to the writer that the behavior of the nymphs with respect to light and 

 contact may not be entirely of a reflex mechanical nature. Such movements 

 are not always precise and definite ; sometimes they are considerably modified. 

 May they not, as Homes has shown with respect to Panatra, possess some of 

 the concomitants of the pleasure pain-reaction? The two sorts of responses 

 seem to be beneficial to the nymphs. Such responses not only aid in conceal- 

 ment from enemies, but also assist in obtaining food. Beneficial reactions are 

 frequently "pleasureable," at least they are not usually "painful." On the 

 other hand injurious resjionses are often "painful," certainly not "pleasant." 

 The nymphs are guided fairly well by their "likes" and "dislikes," if such 

 terms may be used. 



THE NORTH AMERICAN DRAGONFLIES OF THE GENUS ^STHNA 



University of Toronto Studies Biological Series 



E. M. WALKER 



The first part of this work is taken up with a detailed account of the 

 genus Aesthna, being nuiinly a study of the general life history. Then 

 follows a key to the North American species, for both males and females, as 

 well as the known nympiis. Thorough descriptions of the sixteen species are 

 given. There are twenty-eight plates, including six colored plates of the 

 adults. 



Mabel Guernsey. 



UBER VERSONDRUSEN BEI LEPIDOPTEREN 



DR. PAUL SCHULZE 



Zoologischer Anzeiger. April 30, 1912. 



The moulting fluid glands, which have never before been noticed in the 



adult, were discovered in an adult Spilo.soma luteum. These are apparently 



the source of a secretion — probably protective — whicli has been observed on 



the prothorax of certain Lepidojjtera. 



Mabel Guernsey. 



