270 Miscellaneous, 



comparable rather to a scctiou (' scompartemento,' Verson ; 

 * Sameufollikel,' Cholodkovsky) of the corapound testis of the Lepi- 

 doptera." Eut since the cavity of the genital glands is undoubtedly 

 homologous in different insects, the distinction proposed by Koschew- 

 nikoff has no justification whatever. In the form in which he would 

 refute my view in his paper in the ' Zoologischer Anzeiger ' (no. 376 ; 

 Ann. & Mag. Nat. Hist., Feb. 1892:— "The belief that in butter- 

 flies there are uo tracheoe within the testis is erroneous ''), Koschew- 

 nikoff s reply is even devoid of all actual foundation, for I never 

 said that there are no tracheae within the testis : I merely main- 

 tained, as I do still, that into the cavity of the testis, where balls 

 and bundles of spermatozoa lie, the tracheae do not penetrate. 



The spermatogeny of Laphria is of a very peculiar kind, which 

 vividly reminds us of the process described by Verson for Bomhyx 

 mori*. In the blind club-like swollen end of the testicular tube 

 lies a colossal cell, visible with the naked eye ; this is the sperma- 

 togonia, from which the entire contents of the testis are derived. 

 In Bomhyx this spermatogonia is found in the larval stage, but in 

 Laphria it remains active in the imago and exists simultaneously 

 with numerous comjjletely developed bundles of spermatozoa, which 

 distend the middle and lower sections of the testicular tube. From 

 this cell proceed ray-like outgrowths of plasma (as in the case of 

 Bomhyx mori), in which numerous nuclei are imbedded. I have 

 never found a single large nucleus (Verson) in the central mass of 

 the plasma of the spermatogonia, but always several large nuclei of 

 irregular and very varied form, which took either a slight or a very 

 deep stain from carmine. In addition to this I always found in the 

 central plasma-mass of the spermatogonia numerous small chromatin 

 corpuscles, which sometimes appeared somewhat curved and were 

 frequently united into little heaps. Judging by these figures the 

 division of the nucleus in the spermatogonia of Laphria is not ami- 

 totic (as described by Verson for Bomhyx mori), but is effected by 

 typical mitosis. 



As regards the other groups of Diptera, my knowledge of the 

 finer structure of the sexual apparatus is at present still incomplete. 

 I therefore here venture to say only a few words as to the testes of 

 the genus Calliphora. In these flies the two testes are each enclosed 

 in an orange-yellow capsule, and in addition to this are surrounded 

 by a special saccule of the fat-body. Within this saccule, that is 

 between its wall and the testicular capsule, lie peculiar cells of very 

 large size, whose plasma contains numerous large globules, which 

 are apparently hard and take a very deep stain from fuchsine. The 

 significance of these remarkable cells appears at present quite 

 enigmatical. — Zoologischer Anzeiger, xv. Jahrg., no. 391, May 10, 

 1892, pp. 178-180. 



* E. Verson, 'La spermatogenesi nel Bombyx mori,^ Padova, 1889; 

 Verson, " Zur Spermatogenesis," Zool. Anzeiger, 1889. 



