398 



LECTURE XVIII. 



Male organs, 

 Athalia centifolia. 



we have the same characteristics; the testes (a, a) are two in num- 

 ber, but lobulated ; the sperm-ducts {b) slightly ^^ ^^^ 

 expand, and are convoluted into a kind of epi- 

 didymis (c), answering to the reservoir in the 

 hive-bee ; from this part the duct (d) extends 

 to the neck of the prostatic sac (e), which re- 

 peats the bent form. The short ductus ejacula- 

 torius (/) terminates at the base of a virile or- 

 gan {h) covered by two pointed plates (m) beset 

 with soft hairs. Above these are two other 

 irregular double jointed plates (l), folded some- 

 what fan-wise, and furnished with horny hooks. 

 Between these are two muscular parts, which 

 immediately enclose the intromittent organ. 



As an example of the male apparatus in the 

 order Hemiptera, we may take that of the 

 Aphis. The male insect is winged, and is com- 

 monly smaller than the winged female. Tlie internal organs of the 

 male consist of six oval testes, two larger and four smaller, so closely 

 impacted together as to resemble a single sexlocular organ. Ti:e 

 two gently convoluted sperm-ducts proceed close together from the 

 testes and open externaUy, in common with the ducts of two long, 

 colourless, C£ecal appendages, upon a soft, unarmed penis. These 

 appendages never contain spermatozoa ; they are a simple form oi 

 accessory prostate. The spermatozoa are found in various degrees 

 of development in the testes ; when fully developed, they form oval 

 bundles of very fine filaments, which separate in w^ater, at one end 

 expanding like a bunch of flowers. The intromittent organ is not 

 broken away in coitu, and the male aphis may, therefore, enjoy a 

 frequent repetition of the act. 



The tree-bugs {PentatomidcB) have two simple pyriform testes, 

 often of a beautiful red colour : the ground-bugs ( GeocoriscB) have 

 seven long testicular tubes united in a fan-like manner. The testes 

 are numerous, and similarly fasciculate, in the CicadidcB, Kotonecta 

 has two pairs of long spiral tubular testes : Nepa and Ranatra have 

 five flexuous testes on each side. The prostatic glands are largely 

 developed in most Hemiptera. 



Amongst the Neuroptera the testes of the May-flies (Ephemeridce) 

 and Dragon -flies {LihellulidcB) consist of a multitude of round fol- 

 licles, disposed botryoidally around a long dilated portion of each of 

 the sperm-ducts : the prostates are absent. In Panorpa the testes 

 are simple and ovoid : in the Ant-lion {Myrtneleo) they consist 

 of tufts of round follicles surrounded by a capsule ; the sperm- 



