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Nervous System. 



Apart from the reduction of the optic nerve, there is no essential diiference 

 from the nervons system of the earwigs and Arixenia. The main chain consists 

 of eleven ganglia, inclusive of the brain : two cephalic, three thoracic, and six 

 abdominal. The snboesophageal ganglion lies nnderneath a strongly developed 

 tentorinm (/f, PI. XVI [1. fig. :.';, which rcsemlilcs the tentorium of the earwigs 

 and Ari.rotia. 



Reproductive System. 

 The sexual organs of both the male and the female of ILuiumenis present 

 very striking features. However, we know the internal organs of the reproductive 

 system of but few earwigs, and tlierel'ore we should always bear the possibility 

 in mind that similar features may occur in that group. 



Male. The riglit and left testes are alike {ts, PI. XVIII. fig. .)). They 



are large, and have the position as in our figure (the left testis is not drawn). 

 The testis consists of two follicles coiled up together, as shown in our figure 

 (dorsal aspect). The vas deferens (/v/, PI. XVIII. fig. o) runs backwards as far 

 as the convolution of the stomach, and thence turns straight forward, being dilated 

 into a small vesicula seminalis before meeting the vas deferens of the other side. 

 The two vasa are then coiled up together and united, a single duet leading into 

 the narrow channel of a large muscular body, which is the beginning of the ductus 

 ejaculatorius, and may serve as a kind of reservoir {re, PI. XVIII. tig. o). The 

 ductus ejaculatorius emerges from this organ on the left side and soon enters 

 the strongly developed copulatory a[)paratus. The inner half of this apparatus 

 consists of three large bundles of muscles — namely, two bundles of transverse 

 muscles {tm) and one central bundle of longitudinal ones {Im). There is, moreover, 

 on the dorsal side, and lying on the top of the muscles, a broad, thiu chitinous 

 lever {lev), the edges of which are strongly chitiuised and unite with the dorsal 

 edges of the chitinous ventral valves of the external part of the organ of copulation. 

 The sclerites surrounding the penis {pe) are a long dorsal, central plate, which is 

 but feebly chitiuised, and two ventral jilates, the valvae. The latter are very 

 strongly chitiuised, and are divided into an inner and an outer portion, as shown 

 in fig. 4 (ventral aspectj. Both valvae end in a hook, the left hook being mure 

 curved than the right one. The apex of the penis {pe), with its two orifices, 

 is asymmetrical, and bears numerous small teeth direct inward. The ductus 

 ejaculatorius seems to divide where it enter.s the outer half of the organ of 

 copulation ; but I am not sure on that point. 



Female. Hansen, I.e., discovered the skins of six embryos of different 



sizes in a female which he had cleared with caustic potash, and gave a fairly 

 accurate figure of the largest of them. The most remarkable feature they 

 presented is an organ situated between the head and the pronotum. To the 

 best of his understanding, says Hansen, this organ must be in connection with 

 the interior wall of the female genital organs, and thus serve the nutrition of the 

 young, which are growing to an astonishing size, this peculiar gestation being 

 unique among insectti. As the tissues of the mother and embryos were destroyed 

 by the process of clearing, Hansen could not elucidate the matter any further. 



The organs of reproduction of the female are symmetrical. We give a view of 

 them ill situ (PI. XVIIl. tig. 2). The ovaries lie along each side of the stomach. 

 They are very large, and each consists of eight tubes placed subvertically and 

 leaning frontad, partly covering_tJie_8iatnagh....Fig. 8 of PI. XVIIl. gives a view, 



