158 DESCRIPTIONS OF PREPARATIONS. 



tibiae have a pair, the posterior two pairs, of distal posterior spurs. The tarsi are 

 six-jointed, and not clothed with hairs like the rest of the limb. 



The abdomen consists of ten somites. Each consists of a strongly chitinised 

 tergum and sternum united laterally by a soft pleural membrane. The first of 

 the series in both sexes, the ninth and tenth in the male, the seventh to the 

 tenth in the female, require more notice. The first is firmly united to the meta- 

 thorax. It is constricted, and its tergum is divided into a median and two 

 lateral pieces, a division brought about apparently by the attachment of muscles. 

 A slight groove and a difference in the chitin mark its separation from the second 

 tergum. Its sternum is incurved and continuous with the second sternum. 



The ninth somite in the male is inclosed by the eighth. It consists of two 

 narrow lateral chitinous bands which meet with expanded ends dorsally and ven- 

 trally. Each band consists of a median, a dorsal and a ventral piece, the whole 

 forming an S-shaped figure. Strong muscles are attached to these pieces. The 

 "valves which inclose the male genital organ and the anal papilla are attached to the 

 posterior edges of the ventral pieces. Each valve is trigonal, concave internally, 

 its margins fringed with long hairs. Near the ventral edge of its inner surface is 

 a curved chitinous lamella, feebly toothed, the harpe of Gosse (?=harpagon of 

 White). To the posterior edges of both dorsal pieces of this ninth somite is 

 articulated a stout decurved pointed process terminating in two hooks, the uncus of 

 Gosse or tegumen of White. It immediately overhangs the slender anal papilla. 

 A band of chitin connected with the base of the uncus, and continuous from side 

 to side, curves under the same papilla, and from its mid ventral-point project two 

 slender rods which appear to correspond to the scaphium of Gosse. The penis 

 projects from the cavity below, i. e. in front of these rods, and above, i. e. behind 

 the ventral union of the pieces of the ninth somite. The uncus appears to corre- 

 spond to the cremaster of the pupa, the anal valve of the caterpillar. The bar 

 curving below the anus may be either a chitinisation in the tenth or anal somite, 

 or a dissociation from the ninth. 



In the female the seventh somite is much elongated. Its sternum is small 

 and triangular, its pleural membranes large and meeting posteriorly and ventrally. 

 Somites eight, nine, and ten are inclosed by it. The eighth is short dorsally, long 

 ventrally. It has a small pleural membrane. Its sternum is strongly chitinised, 

 grooved ventrally, and the groove narrows anteriorly, serving as a guide to the 

 large orifice of the bursa copulatrix. The ninth somite is soft in texture. A very 

 narrowband represents its dorsal and lateral regions; its ventral region is thick- 

 ened with a linear ventral groove. The tenth somite is represented by a large 

 papilla slit vertically. Its sides are thickened, rough and pilose, and in the slit the 

 anus opens above and the vagina below *. 



1 De Lacaze Duthiers, in his series of classical papers on the genital armature of female 

 Insecta, places the aperture of the bursa copulatrix of the Lepidoptera behind the sixth somite, 

 instead of behind the seventh in the sternal region of the eighth, its ordinary position in Insecta 

 (see the table on p. 230, A. Sc. N. (3) xv. 1853), except in Ephemeridae, where it lies in the seventh 

 intersegmental membrane. De Lacaze Duthiers does not recognise the altered first somite nor the 

 exact position of the orifice of the bursa. Newport recognises the first somite, but has not 

 described the differences between the male and female. His figures (Figs. 391, 392, pp. 922, 923, 

 Article Insecta, cited below) are from a male. The correctness of the view taken above may be 

 gathered partly from the account given of the pupa, partly from the relations of the spiracles (infra). 



