THE CANADIAN ENTOMOLOGIST 387 



NOTES ON STAUROPHLEBIA RETICULATA BURM. 



* 



BY E. M. WALKER, TORONTO. 



Mr. E. B. Williamson, of Bluffton, Ind., recently placed in 

 my hands for study a series of the large Aeshnine dragonfly, Stauro- 

 phlebia reticulata Burm., taken by himself, his father (the late Mr. 

 L. A. Williamson) and Mr. B. J. Rainey in four localities, viz., 

 Los Amates, Guatemala; Baracon, Chaquamas, Trinidad; Rock- 

 stone, British Guiana, and Tumatumari, British Guiana. 



On handing over the series to me, Mr. Williamson called rny 

 attention to the marked difference in coloration between the British 

 Guiana specimens and those from the other localities, and stated 

 that this difference was much more conspicuous in the living 

 insects, being readily recognizable during flight. It seemed, there- 

 fore, desirable to make a careful study of the material in order to 

 determine, if possible, the systematic status of the two colour- 

 forms. 



While pursuing this object, I have also taken the opportunity 

 of studying the mutual adaptation between the peculiarly special- 

 ized structure of the male abdominal appendages and the correlated 

 parts of the head and prothorax of the female, which are held by 

 these appendages during copulation; especially in view of Mr. 

 Williamson's observations on the habits of this species during the 

 copulatory act (vide inf.) 



Coloration. 

 On the envelope containing one of the males from Rockstone, 

 British Guiana, is the following field-note: "Thorax and head 

 bright grass green, segments 1 and 2 similar, shading into yellowish; 

 3-9 golden-brown, clearest on each segment anterior to transverse 

 carina; posterior to transverse carina shaded into brown; 10 largely 

 yellow." 



With one of the Trinidad specimens is the following note : — 

 "Colours like British Guiana specimens, but abdomen distinct- 

 ly bluish-green, very different from British Guiana specimens, so 

 much so that colours in flight are very different." 



The Guatemala specimen bears the following note: — 

 "Eyes bright green, face greenish-blue, thorax dull green, 

 abdomen after transverse carina on 3 dull blue." 



December, 1915 



