NOTES ON RURALID PUP.E. 221 



Notes on the cremaster of certain Ruralid pupae (with two plates). 



By Dr. T. A. CHAPMAN. 



(1) Ruraijs betul.e (Portion of the cremastral area x 100). 

 PL viii., fig. 1. — In this and other similar preparations, there 

 is an irregular fracture due to forcing the pupal skin to a flat 

 surface, to enable it to be easily examined and to be photo- 

 graphed. In this case, less than half the area is broken away. 

 The greater part of the photograph is of the dorsal portion of the 10th 

 abdominal segment, with a pale (less chitinised) band, and a darker 

 terminal portion, on both these the cremastral hooks (?), reduced to 

 very short blunt hairs, are seen. The plate is not quite clear enough 

 to demonstrate it, but it may be seen that they originate at the inter- 

 sections of the fine ribbings of the skin sculpture. There is a Large 

 lenticle in the middle of the dark area, and one also in the pale area 

 (to left of lower part of dark area). There are also two on the ventral 

 area (to right). These are all repeated on the opposite side of the 

 specimen, but are not symmetrical, i.e., they are near the same place 

 on the other side, so near as to appear to correspond, but are 

 sufficiently distant to make it possible they do not. Down to the 



. i.e., above or dorsal to the pale band, fine skin-spiculse come out 

 well in the plate, as well as the ribbing of the skin-sculpture and the 

 points they carry. 



(2) Callophrys rubi (Portion of cremastral area x 100). PI. vii., 

 fig. "^. — We have, here, both sides of a fracture running through a portion 

 of the cremastral region. This photograph, and the plate reproduces 

 it fairly satisfactorily, illustrates at least three very remarkable points, 

 that give this structure so much interest in the pupa of Callophrys rubi. 

 In the first place, no one has noted that this pupa ever takes any 

 attachment by its cremaster, I have never seen any indication of 

 anything of the sort, and I have handled a, good many pupae of the 

 species, yet the pupa possesses a good many very well-developed anchor- 

 hooks of the pattern usual in the Theclid group, and, one would say, 

 obviously quire capable of functional use. The two other points, 

 however, afford support to the view that the cremaster is not used, and 

 has reverted to more simple conditions, except, most extraordinarily, 

 in the structure of the hooks themselves. The first of these items is 

 that the hooks are, more plainly than in any other species I have 

 examined, developments from the points that exist at the crossing of the 

 skin reticulations, and have, therefore, no direct relationship with the 

 ordinary hairs; with ( '. rubi before us to suggest the enquiry, one may 

 note a similar condition in other species, but not pointedly enough to 

 call attention to the structural fact. The other item is equally m 

 illustration that the cremastral area is reverting to ordinary skin 

 conditions; this is the occurrence amongst the anchor-hooks of the 

 cremaster, of ordinary hairs, as usual, unattached to the reticular ribs. 

 I do not know any pupa that has ordinary hairs mixed with the hooks 

 of a functional cremaster, however closely they may approach it. It is 

 to be observed, that the hairs are so much longer than the hooks that 



would probably much embarrass, if not prevent, their proper 

 functions, if its exercise was desired. 



Sitiymon i'kini (Portion of the cremastral area x 100). 

 PI. vii., fig. 1. — Like the others figured a fractured portion, which fails 

 October 15th, 1907. 



