94 M. (X Strobelt on the Anatomy and 



these three nerves on each side ; the last one, however, pos- 

 sesses several more. In the first place two nerves on each 

 side issue from the middle of the lateral parts of the posterior 

 thoracic ganglion ; these were also observed by Landois in 

 Phthirius inguinalis and Pediculus vestimenti, and regarded by 

 him as "transverse 77 nerves, " the function of which is to 

 supply the dorsal vessel and the tracheal stems*" Besides 

 these, nerves are attached to the hinder part of this last gan- 

 glion, five on each side, forming the so-called u cauda equina. 

 These are elongated nerves, which soon divide up into fine 

 threads, and the extremities of which run to the intestines as 

 well as to the generative organs. 



The colour of the ganglia is u dark granular." Each 

 ganglion is surrounded by a special, tolerably thick, struc- 

 tureless envelope. The cerebral ganglion and the first two 

 thoracic ganglia show two probably amalgamated lateral 

 halves, while the last thoracic ganglion consists of three parts, 

 two lateral anterior ones and a narrow hinder one. For the 

 rest I would adopt the views of Landois (24, p. 25), who 

 says : — u The two anterior ganglia and the anterior halves of 

 the third evidently correspond to the three thoracic segments ; 

 the hinder part of the third I regard as the contingent belong- 

 ing to the abdomen." 



Female Sexual Organs. 



The female generative organs consist of the ovaries, the 

 tubce, the uterus, the vagina, and the cement-glands. 



Upon the diverticula of the bicornute uterus five ovarian 

 tubes arise on each side. In our animal these are bilocular. 

 Whether thi3 is the case throughout the genus ffcemato- 

 pinus I cannot say, as I have hitherto only examined a few 

 species of the genus in this respect. In those examined 

 (H. suis, H. eurysternus, and others) , however, I have always 

 found bilocular ovarian tubes. But in the structure of the 

 ovaries in general there is a great difference, the impor- 

 tance of which in the classification of the Lice must not be 

 underestimated. Thus in Phthirius Landois found unilocular, 

 and in Pediculus septemlocular ovarian tubes. Should we, 

 therefore, find in animals of the genus Hcematopinus ovarian 

 tubes possessing more or less than two chambers, this would 

 be a reason for grouping the species in question in another 

 genus. However, at present we know so little about the 

 internal anatomy of the Pediculina, that we must content our- 

 selves with the existing arrangement in accordance with 

 purely external characters. We should, however, act very 

 one-sidedly if we were to found a classification of the Lice 



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