CHAPTER III 



AQUATIC HYMENOPTERA 



DOWN to the year 1862 the large orders of Hy- 

 menoptera and Orthoptera had not been ascertained 

 to contain a single aquatic species. 1 Since that date 

 the Orthoptera have been found to include some 

 semi-aquatic Grasshoppers native to Ceylon and Java 

 (genus Scelymena). The Hymenoptera have proved 

 to contain quite a number of forms parasitic upon 

 aquatic Insects. Amongst these are two minute 

 Insects, described by Sir John Lubbock in the paper 

 cited above. Polynema natans 2 was found swimming 

 in pond-water by means of its wings. It lived several 

 hours under water without sign of inconvenience, 

 though provided with air-tubes, and breathing 

 apparently through spiracles in the usual manner. 3 



1 Lubbock, Linn. Trans., Vol. XXIV. p. 135 (1863). 



2 Westwood (Linn. Trans., 2d Ser. Vol. I. p. 584) thinks that 

 Sir John Lubbock's Polynema should be placed in the genus 

 Anaphes. 



3 This is Lubbock's account. Ganin, in the paper cited 

 below, says that there is no trace of tracheal tubes in any 

 stage. The wings, he adds, are hollow sacs filled with blood, 

 and act as gills. 



