lOO NEW YORK STATE MUSEUM 



terior five or six segments of the embryo were semitransparent 

 and the ocular spots represented by minute, brownish, submedian, 

 pigmented areas. The next day the three-rowed condition, indi- 

 cating the development of adipose tissue, was more apparent, while 

 the lobed posterior extremity of the embryo was fairly definite. 

 On the 30th developing salivary glands were distinguished near 

 the anterior extremity of the adipose tissue. Free movements of 

 the embryo were noted the 31st, and on February ist it was seen 

 that the head was well developed though semitransparent, the 

 antennae having a length twice the diameter. The mesodermal 

 tissue was obscured or absorbed to a considerable extent by the 

 developing sublateral masses of adipose tissue. The head of the 

 embryo was slightly infuscated on the 2d and the ocular spots 

 purplish brown. Free movements of the embryo continued and 

 on the 6th the mesoderm was largely concealed by adipose tissue. 

 There was comparatively little development from this date onward, 

 though the embryo continued active in the mother larva till the 

 loth. Owing probably to an insufficient supply of oxygen it was 

 unable to escape. 



One larva (H) separated January 17th, contained two embryos, 

 each with a length about half that of the mother larva and both 

 showing a distinct infolding near the middle of the germinal 

 streak. The posterior extremities of these embryos showed several 

 exceptionally large, compound cells — polar cells. Six were ob- 

 served in the anterior embryo and apparently three in a row in the 

 posterior embryo, the latter apparently moving anteriorly. Un- 

 fortunately this promising larva was accidentally destroyed. 



Larva I, isolated January 17th, contained an embryo extending 

 from the fifth to the eleventh body segments of the mother larva. 

 The next day four presumably polar cells were recognized at the 

 posterior extremity. There were no evident streaks in the em- 

 bryo. On the 19th one very large aggregation of unusually dark 

 cells was observed just before the posterior extremity, the opposite 

 extremity being largely filled with globular ectodermal cells, espe- 

 cially abundant on one side. The following day a distinct tract of 

 darker tissue was observed on one side of the embryo, extending 

 from its anterior third to its posterior fifth and representing ap- 

 proximately the area occupied by the mesodermal tissue. January 

 2 1st the embryo extended from the fifth to the anterior margin 

 of the thirteenth segment of the mother larva. There was a dis- 

 tinct fold of ectodermal tissue, presumably in the region of the 



