May,'o6] ENTOMOLOGICAL NEWS. 145 



In Proc. U. S. Nat. Mus. Vol. XXVIII, p. 175, I have 

 discussed pruinescence as a sex mark and signal. The pruin- 

 escence of the apical abdominal tubercles of male Argias 

 serves another purpose, i. e. , that of making more secure the 

 coupling of the sexes. Females separated from the males 

 usually have a whitish spot on the mesepisternum where the 

 tubercles of the male have rested. The above description in 

 coupling in group BB shows at once the reason of the inability 

 of the male to release the female at will. How secure this 

 coupling is may be known from the fact that I once captured 

 a female Enallagma exsulans to whose thorax was attached 

 the last nine abdominal segments of the male. Possibly a bird 

 or fish had snapped away the remainder of the body of the 

 male. 



The above notes are tentative in so far as I have positively ex- 

 amined coupling in a limited number of species. To what ex- 

 tent the superior appendages of the male grasp the mesostigmal 

 laminae of the female in Agrioninae is difficult of determination. 

 In local species I believe it is very slight, though the append- 

 ages, of course, rest securely against the laminae, so held by 

 the pronotum. In many species of Enallagma and Ischnura 

 the presence of hooks or teeth on the inferior surface of the 

 superior appendages indicates that these appendages engage 

 closely the rear surface of the hind lobe of the pronotum 

 where they would be held securely by the opposite pressure 

 of the inferior appendages on the anterior surface of the hind 

 lobe of the pronotum. 



Though the subject of Odonate copulation has been con- 

 sidered by many authors with ' presque toujours une descrip- 

 tion detailee et souvent poetique,' I have been unable to find 

 any statement concerning the filling of the seminal vesicle of the 

 male dragonfly, other than that this takes place before copula- 

 tion. In the case of Calopteryx , Argia and Enallagma, where 

 I have been able to make positive observations, the male fills 

 the seminal vesicle at once after he has captured the female. 

 It seems probable that during the wild flight of mating Aeshnas 

 and some of the Gomphiues (I have noticed especially /V<w,>- 

 gomphns spoliatus) the seminal vesicle is being filled, and, this 



