522 MEDICAL ENTOMOLOGY 



forwards to bring his posterior segments on a level with the opening. 

 The operation is carried out so quickly that it is not possible to obtain 

 final proof by killing the pair in copula, but repeated observations on 

 many separate occasions have left no doubt in the minds of the writers 

 that the male organ is actually introduced into the opening of Berlese's 

 organ. 



Further evidence is afforded by an examination of the organ immedi- 

 ately after copulation of this sort has been actually observed. In every 

 case the lumen has been found distended with a mass of sperms, which, 

 when dissected out in saline, show active movements of the usual kind. 

 Sections of Berlese's organ removed immediately after copulation have 

 also been made, and confirmed the result of dissection. Under no other 

 conditions has the same mass of active sperms been found inside the 

 organ. 



Berlese states that the spermatozoa are ingested and destroyed by the 



cells of the organ, and gives figures showing them within the cells ; 



this has not been confirmed so far, but bodies which may be the 



products of the digestion of the sperms have been frequently observed, 



especially in those cases in which all the cells of the organ are enlarged 



and vacuolated. As was stated above, no aperture or duct connecting 



the ovaries or the abdominal cavity with the organ has been found, and 



consequently no explanation as to how the sperms leave the lumen is 



forthcoming. In one case, however, the mass of sperms was seen to be 



very near the periphery of the organ, as if it were pushing its way through 



en masse. That the sperms do actually leave the organ is quite certain, 



for they are to be found in little clumps (Plate LXV, fig. 3) within the 



abdominal cavity in almost all mature female bugs, lying free or attached 



to the viscera ; those at the edge of the clump always show active lashing 



movements. Berlese appears to have noted the presence of these 



masses, which are often large enough to be visible to the naked eye, and 



regarded them as spermatozoa on their way from the spermatheca to 



the organ destined for their destruction, whereas, if the phenomenon 



described above is really copulation, the sperms are travelling in the 



reverse direction. 



These masses of sperms are very characteristic in appearance, and once 

 the eye becomes accustomed to them they can be readily distinguished 

 from fat body. They are to be found all over the abdominal cavity, but 

 in the largest number around the common oviduct, to which they become 

 adherent in larger clumps, often very closely simulating small sacs which 

 might be taken for spermathecae (fig. 4) ; in fact, the authors confess 



