THE ENTOMOLOGIST, 249 



saucer-shaped and situated beneath the larger, and between 

 this and the twig to which it is attached ; the spherical body 

 represents the carpel of the acorn, or the acorn proper, and 

 the saucer-shaped cushion, on which it rests, represents the 

 cupule or cup, or calyx. Having ventured to call the entire 

 gall a pseudo-balanus, or false acorn, so will I call the spherical 

 portion the "pseudo-carpel," and the cushion the "pseudo- 

 calyx." On carefully examining the pseudo-carpel — projecting 

 from it exacly opposite the point of attachment, and there- 

 fore on its summit — will be found a small pointed process, 

 which represents the persistent stigma of the acorn ; and the 

 exterior covering of the pseudo-carpel — tough, leathery, and 

 smooth — represents the pericarp of the acorn. I fail to 

 discover, either on the real or false acorn, the markings so 

 clearly expressed in Dr. Mayr's figure. The resemblance or 

 mimicry of the true cupule by the false one is not very 

 evident ; the relative magnitude of acorn and cup are very 

 different, but the composition is the same. If I understand 

 that of the true acorn correctly, it is made up of a number of 

 involucral scales or bracts, soldered, anchylosed, and com- 

 pressed together into a cupular form ; and this I believe to be 

 equally the explanation of the mimetic cupule. As in the 

 true acorn, a vertical section will bisect the stigma, the 

 carpel, and the cupule, showing that there is the same method 

 in the arrangement of the parts of the false and true acorns. 

 Until a year or more has elapsed I can find no tendency to 

 dehiscence at the base of the pseudo-carpel, but during the 

 second year I have repeatedly observed this dehiscence, the 

 pseudo-carpel falling to the ground like an acorn, and 

 exhibiting a cicatrix at its base, while the cushion, cupule or 

 pseudo-calyx, retains its adhesion to the twig. This is also 

 the case with the Alep])o galls, Cynips gallae-tinctoriae, which 

 dehisce and i'all in numbers every autumn. 



This is emphatically the species on which the most careful 

 observations have been made, with a view to settle the 

 doubtful point, whether or not the species is continued from 

 year to year by a succession of females only, or whether 

 males do exist in alternate generations or in some undis- 

 covered form. The latter seems the more reasonable con- 

 jecture, and I think was first promulgated by the late Mr. 

 Walsh, at p. 320 of the second volume of the ' American 



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