ACCOUNT OF THE PHASMIDAE, WITH NOTES ON THE EGGS. 



77 



The ovipositor and female genital appendages. The genital structures in Phasmidae 

 have been too much neglected by entomologists : they have been avoided for the 

 purposes of distinction of species, and their morphology has scarcely been inaugurated. 

 The structures in the male are remarkable for their simplicity, the intromittent 

 organ of the male being apparently a crumpled sac with five or six more or less 

 vaguely defined sclerites in it. In the female the genital appendages are of great 

 importance for distinguishing the species. The two species, Anchiale stolli and A. confusa, 

 much resemble one another externally and appear to have been confounded by 

 entomologists for upwards of a century ; yet the female genital appendages distinguish 

 the two satisfactorily, and the distinction is placed beyond doubt by a comparison 

 of the eggs of the two forms. The ovipositor in certain other forms of Orthoptera 

 — Locustidae and Gryllidae — has been shown to be formed by six gonapophyses, which 

 appear as separate parts in the early stages of the post-embryonic development and 

 subsequently become intimately combined to form the long, projecting ovipositor. Of 

 these six gonapophyses four, according to Dewitz 1 , are appendages of the ninth segment 

 and are really only a single pair secondarily divided ; the other two are appendages 

 of the eighth segment. In the female Phasmidae, six appendages are frequently 

 present but they are never combined to form an organ for the deposition of the egg ; 

 they remain isolated finger-like processes (occasionally becoming so elongate as to be 

 whip-like), and a part of their functions seems to be to hold the egg in the peculiar 

 external uterus in which it remains till the female releases it, or till it is pushed 

 out by the descent of another egg from the ovaries (PI. IX, Fig. 16). These uncombined 

 appendages appear to be homologous with the gonapophyses of the Locustidae as 

 studied by Dewitz. One pair, the inferior, is separate and is anterior to the others 

 in its attachment to the body. If we use Brunner's enumeration of the ventral 

 sternites this pair of appendages belongs to the eighth segment, the ventral plate of 

 which is prolonged to cover the genital appendages and to support the egg. The other 

 two pairs are placed farther back and are merely prolongations of a large ninth 

 abdominal sternite (PI. IX, Fig. 25 c), as is well shown in the figure of the parts 

 of an immature female of the genus Myronides (Fig. 26 b). The tenth sternite is very 

 large, and is more or less deeply divided at the tip. 



The male genitalia are very little known. Owing to the fact that so little 

 material for study is available in the European fauna, nothing appears to have been 

 published as to the organs of copulation. I have examined them in a very decayed 

 male individual of Anchiale confusa, and find them to be remarkable from the existence 

 of a very large sac which is covered by the pouch or receptacle formed by the ninth 

 ventral plate ; this membranous sac is formed by the ventral wall of the body, and when 

 distended is found to consist of two imperfect pouches, portions of which are thickened 

 and chitinised so as to form sclerites. Five or six of these indurated parts exist ; 

 they are quite asymmetric, and no two of them are at all similar ; some of them are 

 secondary projections from the wall of the sac, while others do not project at all. The 

 hinrler margin and the free angles of the tenth dorsal abdominal plate are also armed 



1 Dewitz, Zeitschr. wiss. Zool. xxv. 1875, p. 174. 



