'rHE EUROPEAN ORGYIAS. 199 



cocoons of <>n/!/ia intermedia (a local form of the ericae group), that, 

 towards the non-emergence end of the cocoon, there are remains of the 

 inner diaphragm. This remnant passes from close to the end of the 

 cocoon to about a fourth (in one case nearly a third) of the way up 

 the other side of the cocoon before merging in the general wall of the 

 cocoon, and so cuts off a sexDarate space behind and beside the place 

 where the cast larval skin lies in the main cocoon. This space is 

 collapsed and useless, and is clearly a mere survival of something ; 

 doubtless that something is the outer space of (J. (jonoxVujuia, the 

 second, or ovipositing cocoon of 0. aurolimbata. (). ericae (with (K 

 splendida) has, therefore, made the step beyond these, of the moth 

 remaining in the original cocoon, and not going into the new one. 



The plates and rods of the ovipositors (figured in pi. iv, pi. vi and pi. 

 vii) show that the rods dwindle as the moth specialises. They are no 

 doubt the chief agents in enabling the muscles to direct the various 

 plates surrounding the outlet, so that the eggs may be placed exactly 

 as desired. We find them accordingly longest in O. antiiiua (pi. vi., 

 fig. 9). In (>. (ionosti(iiiia{]A. vii., fig. 8), they have become much 

 reduced, the first by nearly 30 per cent. (Note that in the figure the 

 ovipositor has been opened on the dorsal, instead of the ventral, line, 

 as in the other specimens, and that the consequent separation 

 of the plates of the 9th segment, as compared with the other 

 figures, is a mere result of this and not a peculiarity of 

 (>. (jonoatiiima.) The structure suggests that O. i/onostitpiia still 

 makes some sort of definite arrangement of her eggs when laying, 

 though not by a long way so distinctly as O. antiqua does. 

 In 0. Corsica {ericae group ; pi. vii., fig. 16) there is a much greater 

 reduction of the first rods, which are little more than a third the length 

 of those of O. antiqua, the second rods are still of quite full length, and 

 are, if anything, rather longer in (K tri'iotepJiraH. Has this any 

 relation to the ovipositor having to be extruded from the cocoon ? In 

 (). aiiroliiiibata (pi. ix., figs. 9 and 10) the first rods are very short, and 

 in O. s}ilemlida (pi. vi., fig. 12) practically obsolete. The second rods, 

 though short, are still faidy developed. One would conclude that the 

 second rods (9th segment) are necessary in the mere extrusion of the 

 eggs, whilst the first (Sth segment) are the chief agents in directing 

 the ovipositor for their accurate placing. This is in agreement with 

 the immense development of the first rods that occurs in the Holenobias 

 and Fumeas, &c. When we observe how great the degeneration of (>. 

 s})lendida $ is, beyond that of O. auroliiiibata, much more than the 

 degeneration of that species is beyond that of O. (jonostigina, we 

 understand that there must be a great gap between them in habits 

 and probably some missing stages in the passage from the one to 

 the other. That we cannot very easily form a picture of these follows 

 as a matter of course, the difficulty being increased by the probability 

 that (}. anrolimhata is not the starting-point, but some other possibly 

 considerably different form. 



When we come to the 0. ericae. group I have no first-hand know- 

 ledge of the habits of the species. I, therefore, give here the best 

 account of those I have been able to find. 



Of 0. ruiH'stris I have not been able to obtain any specimens. 

 Those I have had $ specimens of are — (K ericae, (>. cursica, O. trif/ote- 

 phras, 0. intermedia, and 0. anceps. I ought, perhaps, to say rather 



