OF WASHINGTON. 



307 



spicules and other shorter ones ; but they vary less in length than in other 

 species. In the impregnated female there is found within this receptacu- 

 lum, and almost filling it, what appears to be an inner sac with a narrow 

 neck entering and following the neck of the receptaculum. This is doubt 

 less but a combined mass of spermatic particles or fasciculi forming what 

 has been called by Lepidopterists the large spermatophore. The albumen- 

 like wall or envelope of this mass is somewhat thickened as it approaches 

 the hubs of the receptaculum but then suddenly becomes thin and is some 

 what insecurely fastened to the hubs, so that when the spermatophore is 

 detached there is practically an opening in each side at the point where it 

 was attached to the receptaculum. There are three membranes to this 

 receptaculum an external or muscular, a middle or serous, and an internal 

 or mucous. The strong fibres of the muscular coat radiate from the border 

 of the hub of one of the chitinous bodies, and are inserted in a similar 

 position upon that of the opposite side. They thus include the whole of 

 the sac until toward the neck, where they change to circular constricting 

 fibres, and thus continue through the duct. Fig. 13 a gives an enlarged view 

 of this receptaculum, with a longitudinal section through the hubs at b, 

 showing the large spermatophore or inner sac c, the space between it 

 and the walls of the receptaculum, and the manner in which the hub 

 and the radiate spicules are placed at d. In Pronuba yuccasella this recep 

 taculum averages about 1.7 mm. in length, by i mm. in diameter, the 

 crusher or radiate body measuring i mm., the rays averaging 0.43 mm. in 

 length and the hub or axis 0.14 mm. in diameter. By way of exhibiting 

 how very much more strongly developed this receptaculum and its crushers 

 are in yuccasella than those in any other species, I have introduced (Fig. 14) 

 drawings of the similar organs of Pronuba synthetica (a), P. maculata 



Fig. 14. a, outline of receptaculum seminis of Pronuba synthetica ; b, 

 do. of Pronuba maculata; c, do. of Prodoxus decipiens^ all drawn to same 

 scale as figure 13; d, enlarged spicule showing ventral groove and a trans 

 verse section of same. 



