ANOPLURA: THE MALE ORGANS 559 



duct turns upwards to the neck immediately external to the oesophagus, 

 and internal to the duct of the tubular gland. 



In the region of the salivary glands there is a large amount of fat 

 body, arranged in long and irregular lobules of an opaque white colour. 

 These are closely adherent to the salivary glands and the ducts, and 

 render dissection of this region a somewhat difficult matter. Embedded 

 among the fat body, immediately anterior to the kidney-shaped glands, 

 there is on each side a small collection of round cells (Plate LXX, fig. 2), 

 readily distinguished from the fat body by their more glistening appear- 

 ance. These are constant in position, and are always found, in sections 

 and dissections, surrounding the oesophagus, though not attached to it in 

 any way. They have no capsule, but appear to be connected with one 

 another by short and pointed processes. The protoplasm of these cells is 

 vacuolated, and contains many fine granules. One, or sometimes two, 

 nuclei are present, and appear as clear vesicles containing a darkly 

 staining central mass of chromatin. No duct has been distinguished 

 with certainty, though in some dissections a fine filament which may 

 perhaps be a duct has been noted passing upwards with the salivary ducts. 



The reproductive organs of the louse present some interesting pecu- 

 liarities. The male organs are quite unlike those of other insects. 

 There is a pair of testes on each side ; each is a small 



oval body, and the two of each pair are closely apposed Reproductive System. 



,, , ,, . , j j AU j , The Male Organs, 



to one another by their broad ends. The vas deferens p|ate LXX| 



of each side arises at the point of junction of 

 the pair, and passes directly to the posterior end of the abdomen 

 as an extremely fine tube, much finer than could be represented 

 in the drawing (Plate LXXI, fig. 7). The receptacula seminis are 

 also paired, each receiving the vas of its own side ; they are long 

 tubular structures, slightly narrower at the posterior than at the 

 anterior end, and lie parallel to one another in the middle ventral 

 region of the abdomen, reaching almost as far forwards as the 

 testes. The vas of each side enters its receptaculum at the narrow 

 posterior end, and here there is on each side a small conical accessory 

 gland, attached to and apparently continuous with the receptaculum ; 

 in fresh preparations the gland and the receptaculum have the same 

 appearance, and it is only in stained preparations that one recognizes 

 the difference in structure. At the anterior (or distal) end each 

 receptaculum becomes continuous with an efferent duct, without any 

 diminution in the calibre at first ; after a very short course these 

 ducts turn backwards in a ventral direction, and at once become 



