18 



male from which the legs have been lost in mounting the specimen, a 

 mutilation which our experience with the birch coccid shows is very- 

 likely to take place. 



In view of the close coincidence in such details as are given by Loew 

 between Xylococcas filiferus and the coccid described in these pages I 

 have no doubt whatever that the same transformations will be found to 

 occur in both, and that our coccid of the birch is a species of Xylococcus. 

 The remarkable tubular ninth segment, which in Coelostoina Maskell 

 calls a honey-dew organ, is a character which will probably unite those 

 coccids which are found to possess it in the same subfamily and indi- 

 cates an approach to the Lecaninse, in which the ninth segment is also 

 internal and similarly modified. In the Lecaninre, however, the penulti- 

 mate segment is also modified and transformed into the two anal 

 valves, and the eighth abdominal segment terminates the body behind. 

 Many interesting suggestions arise as to the affinities between these 

 coccids and the lac insects (Carteria, etc.), which approach yet more 

 closely to the Lecanid type, and on the other hand as to their relation- 

 ship with the Monophlebids, which are supposed to have no modified 

 anal segment and the ninth segment terminal in all stages. 



It is apparent, however, that in Xylococcus and Ccelostoma we have 

 to do with a subfamily of Coccidre not hitherto recognized, and to which 

 no doubt will be added other genera at present included in the hetero- 

 geneous division Brachyscelidae and also in the Monophlebinse. Our 

 knowledge of the metamorphoses in these exotic insects is in almost 

 every case quite incomplete. In many the intermediate stages remain 

 unknown. 



Since the foregoing pages were written Mr. Pergande has continued 

 the observations which we began in common, and, with the acuteness of 

 research which characterizes him, has discovered an additional stage 

 in each sex, the most noteworthy being the legless third stage in the 

 male series. Through his courtesy I have been enabled to correct my 

 preliminary notice to correspond with his detailed descriptive paper 

 which follows. 



Part II.— By Th. Pergande. 



(Xylococcus betulce Perg.) 



After Mr. Hubbard and I had, as we supposed, concluded our obser- 

 vations upon the transformations of this very remarkable coccid, I was 

 enabled, by further study of the living material at hand, to recognize 

 an additional stage in each of the two sexes, raising those of the 

 female to five and those of the male to six stages. 



In our preliminary studies some apparently slight differences had 

 been observed in what we considered to be the second and third stages, 

 but we supposed them to be simply due to a greater or less develop- 

 ment of individual specimens of the female series. 



Remarkable as the changes of the female are, those of the male are 

 still more wonderful. Up to a short time ago I had been of the opinion 



