182 [July. 



exist, at least in this form. When the great length of the rods in 

 these insects is considered, and that they even reach in some cases 

 as high as the 3rd abdominal segment, it becomes plain enough how 

 inconvenient, if not impossible, it would be that retractors (allowing 

 of the length of range required in these insects) should be inserted 

 in the ordinary way into the points of the rods. Where, then, are we 

 to look for them ? To this I can by no means give a satisfactory 

 answer. Let me, in the first place, say, that I feel nearly positive 

 that the ovipositor has not a special muscle for drawing it back into 

 the abdomen, in addition to its own proper one that retracts it within 

 the sheath, for I have quite failed, after very careful search, to discover 

 anything to which such an office could be assigned. Besides, seeing 

 bow intimate is the connection here between the ovipositor and sheath, 

 and how important the sheath has become as an integral part of the 

 egg-laying apparatus, it appears only necessary to provide for a special 

 muscle for the withdrawal of the ovipositor as far as^the sheath, leaving 

 it to the latter organ to carry it along with itself into the body. But 

 what withdraws the sheath ? That is the crux. That it requires and 

 is effected by special muscles can scarcely be doubted ; and that the 

 muscles must be inserted into the body of the sheath, since the rods 

 are closed to them, is equally certain. Tet I have not been able to 

 find them, or at least, to isolate them from the muscles which pass in 

 and ou'.. of the sheath in connection with the movements of the ovi- 

 positor. I have often, hov^ever, been struck, especially in dissecting 

 the Coleophoree, with the great amount of muscle, broken and unbroken, 

 connected with the sheath. The unbroken fibres, forming much the 

 larger part, can be traced into the points of the rods, and named 

 without hesitation ; but the broken ones are more perplexing. I am 

 tempted to assign them to the muscles we are in search of, their inner 

 attachments to the abdominal wall having been lost by the removal of 

 that structure in the course of preparation. There is yet one point 

 observable in all the long-rodded insects, which ought not to be passed 

 over, viz., the remarkable way in which the muscles sux'round the rods 

 on all sides, encasing them, as it were, in a fleshy tube ; an arrange- 

 ment which not only gives direct support to these long and slender 

 bodies, but also by insuring an even pull all round instead of a one- 

 sided one, must prevent the bending which would otherwise almost 

 certainly occur under the great muscular strain they have to bear. 



I will now describe in detail a few of the instruments I have 

 examined, and shall select them chiefly from the Tineince, purposely 

 avoiding those in wliich the genital aperture is largely developed, 



