( Ixxxvii ) 



The tenth seg-meut is apparent!}' always symmetrical in the Sjjlumjidab with 

 tlie exception of Sesiinae, where it is asymmetrical in a great number of species. 

 The tenth segment of the Si'siinae is normally divided into a right and a left 

 lobe, the tergite {Xt) as well as the sternite (A>) (PI. XLII. f. 1—25). In 

 most species of Sesii/tae the tergite remains symmetrical ; in the highest members 

 of the subfamily it undergoes, however, peculiar modifications. The nearly 

 symmetrical nintii and tenth tergites of Haemoirliagid, and Cephonodes (PI. XLIII. 

 f. 0. 21) become twisted (PI. XLIII. f. 8. 11), and the left half finally nearly 

 obliterates, being represented only by a broad semi-detached swelling {I) at the base 

 of the riglit process (left in figures), as shown in f. 15 — 18 of PI. XLIII. The 

 sternite of llaemorrhagia 'ceinild and Cephonodes janus has two unequal processes 

 (PI. XLIII. f. 12. 14. 2ii) ; tiie riglit one of them disappears, as more fully 

 exfjlained on p. 4(31, there being scarcely a trace left of it (PI. XLIII. f. 25, r), 

 the sternite having a single i)rocess. This ventral process becomes shifted 

 towards the left side in Cepho)iodi's, lying finally in a plane with tlie tergite, 

 and forming with the latter a horizontal forceps (PI. XLIII. f. 8. 9). 



In Ein/o japix (PI. XLIV. f. 7) the sternite has become simple, but the 

 left process has not entirely disappeared. In Himaiitoidea, also with a simple 

 tenth tergite, tlie sternite has ]>reserve(l a remnant of the aborted left process 

 (PI. XLIV. f. 8), which remnant appears as a tubercle on the left side of the 

 sternite beyond the middle of the latter. The sternite of Epistor (PI. XLIV. 

 f. 10. 11) is simple but asymmetrical at the end ; it is doubtless a development 

 from a symmetrically divided sternite, but there is as yet no species known 

 which shows an intermediate stage. In Calliomma pnircf and Leucorhampha 

 ornatus the left process of the sternite is shorter than the right one, wliile in 

 Pnch)/Ua re.'otmens (PI. XLII. f. 6) the right one is a little longer than the left. 

 In all these cases tlie steriiile is in advance of the tergite in the asymmetrical 

 reduction. 



The right and left harpes are conspicuously different in several Si'siinae. 

 Fach/Ua darcefa (PI. XLV. f. 26. 27) has on the left harpe a large curved 

 process, which is represented on the right harpe by a small tooth only. In 

 Aleuron neglectum and Epistor lugubris we find the right harpe produced into 

 a long conical, elbowed process (PI. XLVI. f. 13), while the left harpe is very 

 short (PI. XLVI. f. 12). 'Differences which are not quite so conspicuous are 

 observed in the allied species and genera. Sometimes the claspers are obviously 

 different right and left — as, for instance, in some Epistor. The most remarkable 

 cases are again found in the genera llaemorrhagia and Cephonodes. The latter 

 genus has no free harpes ; the right and left claspers are always dift'erent in 

 size and shape (PI. LI. f. 22 — 25 ; PI. LII. f. 1 — 3), the contrast being strongest 

 in (.'. trochilus. In all Cephonodes, as well as in all llaemorrhagia, the left 

 (right in figures) clasper is reduced or modified. The right and left harpes of 

 llaemorrhagia venata are practically the same (PI. LII. f. 5) ; in the other 

 species the left is always shorter than tiie riglit, the latter being often long 

 and club-shaped, whereas the left one is vestigial (PI. LI. f. 17—21 ; PI. LII. f. 4). 



