308 ENTOMOLOGICAL SOCIETY 



(), and Prodoxus decipiens (c), drawn to the same scale. In P. synthetica 

 the receptaculum averages about i mm. in length and 066 in width; the 

 crusher has a diameter of 0.43 mm., the longer rays about 0.17 mm. in 

 length, and the axis or hub about o. 10 mm. in diameter. The crusher in 

 this species looks much more like a burr, there being 16 of the longer, 24 

 of a shorter size, 32 yet shorter, and a number of the shortest which grad 

 uate into the tubercular inner surface of the hub. In P. maculata the 

 receptaculum has a length of 0.66 mm., and a diameter of 0.5 mm. ; the 

 crusher has a diameter of 0.4 mm., the longest rays a length of about 0.17 

 mm., and the axis a diameter of 0.06 mm. In Prodoxus decipiens the 

 receptaculum has a length of 0.65 mm. and a diameter of 0.3 mm. The 

 crusher measures 0.09 mm., with the longest rays 0.05 in length and axis 

 0.02 in diameter. The axis is relatively longer than in the other species, 

 and the spicules are much reduced in number. 



The object of these chitinous bodies has been somewhat of a puzzle, all 

 the more difficult to solve that they seem to be quite exceptional, and, in 

 the remarkable development which they here present, absolutely unique, 

 so far as I have been able to ascertain. They attracted my attention in 

 my earlier studies of Pronuba and I was glad to find, on visiting Dr. H. A. 

 Hagen in 1880, that he had been very much interested, in his studies of 

 Prodoxus, in the similar but smaller organs of that insect. His explana 

 tion of their function, as elaborated in the Zoologischer Anzeiger (Jan. 

 1882, pp. 18-21), is doubtless correct, viz., that they serve to liberate the 

 spermatozoa from the spermatophores, but he was in error in locating 

 them in the bursa instead of the receptaculum.* The muscular arrange 

 ment which I have described is well suited to such a purpose. In the 

 somewhat flattened receptaculum the spicular arms actually intermingle, 

 and the radiating muscular coat possesses the only arrangement of fibres 

 which would enable a simple contraction to bring at once the whole con- 



* In this paper Dr. Hagen elaborately describes these radiate bodies 

 from both Pronuba and Prodoxus. Aside from the error of locating them 

 in the bursa instead of the receptaculum^ some of his other statements 

 are very confusing in the light of the facts as observed by me. What he 

 calls the inner sac (the large spermatophore) does not occur in the virgin 

 but only in the impregnated female, and yet he describes it from what he 

 insists were virgins, stating that "die drei ersten Schmetterlinge welche 

 auskamen waren Weibchen ; da ich sie untersuchte bevor einige Tage spater 

 Mannchen erschienen, bin ich sicher das sie unbefruchtet waren." He 

 then states that he found the empty space between the inner sac and the 

 inner lining of the outer sac filled, after coition, with spermatophores 

 clustering particularly about the star, while the inner sac and its outlet 

 contained only the hair-like spermatozoa. I cannot explain the earlier 

 statement except as another of the unfortunate errors my good friend has 

 been led into in connection with the Yucca moths. It is so explicit, how 

 ever, that, since this communication was presented, Ihaveagain examined 

 virgin females of both Prodoxus and Pronuba, only to confirm the fact 

 that there is no inner sac to the receptaculum. and that the presence of 

 this sac or large spermatophore is a sure evidence of impregnation. 



