PHILIP P. CALVERT 339 



partheywpe as due to the teeth on the inferior appendage of the 

 male, appHed against the dorsal surface of her head when pairing. 

 These scars (which I also have found in females of A, Junius, 

 A. parthenope and A. imperator) are, he noted, accompanied in 

 some cases wdth a coagulated crust which, he suggested, might 

 be derived from a secretion of the male, or exuded blood or lymph 

 of the female. Dr. E. j\I. Walker has described and figured'-^ 

 the copulatory position of the male appendages of Gomphua 

 spicatus, in which they are represented as being stretched apart 

 rather widely, and I have made some suggestions as to the prob- 

 abilities in Erpetogomphus tristani?^ Dr. C. H. Kenned}^ has 

 figured and briefly described" the manner in which the 

 appendages of the male of the CaUfornian Ociogomphus 

 speadaris clasp the head of the female. In describing Epigotn- 

 phus arinatus, Dr. Ris remarks: "Die Struktur des 9 Occii)ut 

 ist ein sehr schones Beispiel von Anpassung des 9 an die Klam- 

 merfunktion des cf Appendices,"-* although he does not point 

 out the adaptations in detail. 



AvaiUng myself of these observations and suggestions, I have 

 attempted, in the following pages, to correlate definitely the 

 structures of the two sexes when in the copulatory position. 

 I hope that other students may be able to correct or improve 

 upon what is here offered. Epigomphus verticicorms is considered 

 first because the evidence seems fullest for that species. 



Epigomphus verticicornis (PI. XV, figs. 23 to 26.) 



Of Epigomphus verticicornis I have only two specimens, the type 

 male and allotype female from Tuis, taken by Mr. C. H. Lankes- 

 ter, which, as stated in the Biologia volume, p. 410, "conmuini- 

 cated by Prof. Biolley, were taken in June, 1907, and sent en- 

 closed in the same envelope, whence it is concluded they were 

 pairing. " 



This female has on the rear of the head behind the right eye, 

 at about the same horizontal level as the mesal angulation of 



25The North American Dragonflies of the genus Aeshna. University of 

 Toronto Studies, Biological Series No. 11. pp. 41-42, pi. 2, fig 7, 1912. 

 26Enf. News, xxni, pp. 294-295, 1912. 



2^Proc. U. S. Nat. Mus., 52, p. 578, figs. 332, 333, and p. 579, 1917. 

 28Archiv f. Naturgesch., 82 Jahrg., Abteil. A, 9 Heft, ]). 149, 1918. 



TRANS. AM. ENT. SOC, XLVr. 



