184 



[July, 



threads of chitine connected together by inter- 

 vening membrane, and may be likened, from their 

 Btructure and appearance, to an open fan. Tla 

 broader pieces or bands are directly continuous 

 with the rod, but the threads either spring from 

 the bands or arise independently in the inter- 

 spaces, as these become wider by the divergence 

 of the bands. Numerous spiculse come off at 

 right angles from the bands and threads, and 

 others are scattered sparingly over the intervening Fig. 3. 



membrane ; their ofEce being, I presume, to supply the ovipositor with sufBcient 

 transverse rigidity. The inner rods are short and weak, and suddenly expand, before 

 ending in the plates, into an oval-shaped piece, which affords attachment to a part 

 of the proper " retractor " muscle of the ovipositor. The tactile hairs form a thick 

 fringe along the outer edge of the plates, but their number rapidly lessens on the 

 body of the plates, only a few reaching about as far as the middle. Their chief 

 Beats are the bands and threads, but some may also be found on the soft intervening 

 membrane. They may be readily known from the spiculte by their much greater 

 length, their longitudinal direction, but principally by their large, granular-looking, 

 and tubercular bases. 



The substitution to a greater or less extent, of membrane for 

 chitine in the ovipositor, of which the Oeometrce afford an example, 

 is the essential characteristic of the soft ovipositor, in contradistinction 

 to the hard or rigid one: the former is almost universal, and is to be 

 found from end to end of the Lepidoptera, in simple and compound 

 instruments alike, whilst the latter is strictly exceptional, and confined, 

 so far as I know, to some genera in the Tineince. I do not propose to 

 describe other forms of the soft ovipositor. There are many of them, 

 as may be conjectured from the various modifications to which its 

 several parts can be subjected — for instance, in the relative proportion 

 of the parts, in the presence or absence of the expansion for the 

 retractor muscle, the number, form, and disposition of the chitinous 

 ribs, with the presence or otherwise of the spiculje, as well as in the 

 general shape of the instrument itself. To attempt them would add 

 unnecessarily to the length of these articles ; and as I have also 

 already entered sufficiently into the more common forms and modifi- 

 cations of the 8th segment, I may, therefore, pass at once to a 

 consideration of the rigid, compound instruments, which, exceptional 

 though they may be, are from their highly specialized nature more 

 interesting and worthy of our attention. The simplest of them is the 

 lancet-shaped instrument for probing unopened flowers, of which no 



riQS. 2 and 3. — One of the plates of the ovipositor, and the 8th abdominal segment in M. euphor- 

 biata. a, Dilatation for the insertion of retractor muscle of the ovipositor, b. Torn 

 muscular fibres. 



