Testis of Leptinotarsa Signaticollis. 493 



degeneration. Further, the cell fragments are not found mingled 

 with the spermatozoa in the sperm ducts. While I have noted 

 occasionally cysts of degenerated spermatocytes, the fact has no 

 direct bearing upon the matter under consideration. 



All of the literature on the histology of the Coleoptera has not 

 been accessible to me, but in that which has been at my disposal, 

 I have not met with any description or reference to the degener- 

 ation process as I have observed it in the species under discussion. 

 It is almost unnecessary to remark that the appearance of degen- 

 eration is not due to an artefact, the result of the action of fixing 

 agents. The degenerated mass can be detected in all the testes 

 that I have examined in at least two species of Leptinotarsa (sig- 

 naticollis and decemlineata) however killed and stained, and 

 moreover is most distinct and clear-cut in the best preparations 

 as judged by the fixation of the other parts of the organ. 



The cap of epithelial cells from which the degenerated cells arise 

 undoubtedly corresponds to what Demokidoff has described in 

 Tenebrio: "Jeder von den 6 Folliken des Hodens von Tenebrio 

 molitor besitzt ein eigenthiimliches Gebilde (eine Linse) welches 

 aller Wahrscheinlichkeit nach ein der Endkammer der Ovariol- 

 rohren entsprechendes Organ darstellt." But as I have already 

 pointed out, the structure in Leptinotarsa appears to be homolo- 

 gous not with the Endkammer, but with the enlarged base of the 

 terminal thread. 



Similar structures have been described in other species of in- 

 sects, viz., the ''Apicalzelle" of the testes of Diptera and Lepi- 

 doptera, which is located in a similar position in the end of the 

 organ. Griinberg speaks of the ''Apicalzelle" as the nurse cell 

 of the testis, which when its function is completed degenerates 

 along with a few of the germ cells. 



In Leptinotarsa, no cells corresponding to the nurse cells of the 

 ovariole are present. The walls of the cysts are formed of epi- 

 thelial cells similar to those that degenerate, and as the sperma- 

 tozoa mature a number of them become attached to one of these 

 cells. This ''nurse cell" is a greatly enlarged epithelial cell, and 

 not a tricusformed germ cell as is the case in the ovariole. The 



