MALE ORGANS OF GENERATION. 215 



ing portion of the visible sexual organs is the penis (f. 7), consisting of 

 a superior sheath formed by two horny pieces, which are united by a 

 membrane (f. 7- '<O and the central unequal upwardly bent spine, 

 which is furnished at its extremity with a barb (f. 7- ^ ) 



The comparison of this organ with that described in the Coleoplera 

 has therefore now no further difficulty ; the superior and inferior valves 

 are the case of the penis, here indeed entirely transformed, which is 

 united by the withdrawn prepuce to the surrounding parts ; the penis 

 itself lies formed in it, at least in situation, just as we have described 

 it in Dyticus and Hydrophilus. 



In the Hymenoptera I shall first describe the penis of the saw-flies. 

 When in a Cimbcx the last ventral and dorsal plates are removed, upon 

 the dorsal side we immediately meet with the flexible anal valve, be- 

 neath which the anus lies, and then with a fold of the prepuce, which 

 separates the anus from the sexual organs. These are entirely enve- 

 loped in the membranous prepuce, and consist of two large hooked 

 horny bodies, which are united at their base by a flexible membrane ; 

 between these likewise lie the bivalved flexible penis, in which, pre- 

 cisely as in the female saw-flies, the central bone is wanting. The 

 particular form of each single joint is shown in the figures 8 10. of 

 Plate XXVI. The exterior valve consists of two joints (f. 8 and 10. 

 a, b~), the upper one of which is small, triangular, somewhat arched, 

 and membranous; the lower one is larger, and consists of strong horn. 

 Between these lie the broad lobate valves surrounded by a horny ring 

 (f. 8 and 10. c, c), from which the canal of the penis (f. 10. d.~) is con- 

 tinued. 



In Vespa, where we find almost the same parts, we immediately 

 detect an important difference, which is, that the central unequal spine 

 of the penis, or here rather the true penis itself, is present. Figures 

 11 13. of PL XXVI. show the male organs of Vespa Germanica. 

 Two large round valves, to which above there is attached a small 

 spinous process, form, as in Cimbex, the exterior case of the penis 

 (f. 11. a, ). Between these exterior ones the inner ones lie (the 

 same, b, 6) ; these are smaller and more delicate organs, which embrace 

 the penis, they are of the consistence of parchment, and distended at their 

 end into a shovel shape. The penis itself is a delicate bent shovel, 

 which, previous to its dilatation, is provided with two barbs (f. 13. a, 

 ), and has upon its superior side a deep almost tubular channel, 

 through which the semen is ejected. 



