Vol. XXV] ENTOMOLOGICAL NEWS 4/9 



Meeting of September 27, 1914. In the absence of the Di- 

 rector and \'ice-Director, Dr. Phihp P. Calvert presided. Six 

 persons were present. 



Mr. G. M. Greene made some remarks on Sandalus petro- 

 phya (Col.). Mr. Liebeck said he supposed the species was 

 always found on beech. 



Mr. Rehn explained a method of collecting Orthoptera by 

 trapping, recommended by Mr. W. T. Davis, by means o£ 

 setting a Mason fruit jar into the ground with the opening level 

 with the surface. A small quantity of New Orleans molasses, 

 with a few drops of fusel oil, is placed in the jar. He said 

 many little known species are collected by this method, spe- 

 cially mentioned the genus IscJinoptera and made some remarks 

 relating to it. 



Mr. Cresson reported on the progress of arrangement of 

 the local collection. 



Dr. Calvert exhibited specimens of the Odonata Gynacantha 

 gracilis, G. trifida, Pliilogenia carrillica and Protoneura re- 

 missa, all of which he had taken in the same piece of dark 

 forest on the Banana River, Costa Rica, November q, 1909. 

 The actual body lengths of these four individuals is 88, 63, 57 

 and 37 mm. The sizes of their eyes may be appreciated by 

 giving their heights, viz.: 7.44, 5.76, 2.88, i.ii mm. The eyes 

 of the two Gynacanthas meet on the top of the head, those of 

 Protoneura and of PJiilogenia are separated by a distance 

 equal to the width of one eye. In spite of the smaller size of 

 the lenses (facets) in Protoneura. he calculated that roughly 

 the Protoneura eye has only half, or less than half, the number 

 of facets of G. trifida and between three-sevenths and one- 

 third as many facets as G. gracilis. Taking various factors 

 into consideration, he concluded that the eyes of the Gyna- 

 canthas are more efficient organs than those of the other two 

 genera. Since other dragonflies (Anax, AesJiua) with eyes al- 

 most as large as those of Gynacantha. are found in well-lighted 

 places, we cannot suppose that the large eyes of Gynacantha 

 are a result of shadow-haunting habits. Rather must we look on 



