THE STINK APPARATUS OF CIMEX 523 



that they at first regarded them as such, until their attention was arrested 

 by the fact that they could not be stained in the ordinary manner, and 

 that the outline was always hazy. It was only by very deep staining 

 with haematoxylin, and subsequently by cutting a series of sections, that 

 their true nature was revealed. 



With regard to the ultimate fate of the sperms, little can be said at 

 present. The fact that they accumulate around the common oviduct 

 suggests that they are on their way to the ova, and should this 

 be their ultimate destination it would possibly have some connection 

 with the high degree of development which the embryo may attain 

 while still in the ovary. That they are able to pass at will through other 

 tissues seems very likely, in view of their great motility and of the fact 

 that no aperture can be found in either the wall of Berlese's organ or the 

 oviduct. On at least two occasions active spermatozoa have been seen 

 within the lumen of the gut while it was still unruptured. 



As to the true nature and origin of Berlese's organ and its opening, 

 one hesitates to speak : if a suggestion were to be offered, it would be 

 that they represent a survival of paired and segmental genital organs 

 and pores of a remote ancestor. 



The bed bug, like many of its non-biting allies, is provided with an 

 apparatus for the production and emission of an evil smelling fluid, 



the object of which is to protect the insect from its 



TM- ^ r ^-i i j The stink 



enemies. The apparatus consists of a stink gland apparatus 



and reservoirs, and lies in the ventral and posterior 

 part of the thoracic cavity, opening to the exterior at the border of 

 the metasternum. An excellent account of these structures is given by 

 Landois. The stink gland is a small kidney-shaped body, consisting of a 

 number of pear-shaped cells, which are arranged with their broad ends 

 next the wall, their narrow ends directed to the lumen, into which they pour 

 their secretion. The secretion itself is a highly refractile, colourless, and 

 exceedingly malodourous oil. At the point corresponding to the hilum of 

 the kidney there is an opening which leads from the gland to the 

 reservoir. The two reservoirs are elongate and spindle-shaped blind sacs, 

 joined together at their lower ends. When filled with secretion their 

 walls are smooth and taut, but when the oil has been expelled they 

 become wrinkled ; the walls are exceedingly thin. The efferent duct is a 

 strongly chitinized funnel-shaped structure, which leads from the united 

 outer ends of the reservoirs to the exterior, opening between the last pair 

 of legs at the hinder border of the metasternum. The external opening 

 is too small to be seen from the outside. 



