PUTNAM ON PULVINARIA INNUMERABILIS. 299 



middle, something like I have attempted to represent in Fig. 19. I have 

 been under the impression that it might be formed by the inturning of 

 the outer granular layer, but of this I am not certain. I have observed 

 embryos thus far advanced while still in the ovary of the mother. 



This granule mass, or embryonal band, continues to extend backwards 

 until its rear end is again turned forward as shown in Fig. 29. At this 

 stage the anterior or head end is much the largest, composed of larger 

 granules, and lies nearer the surface, while the posterior portion is seen 

 to be gradually more and more deeply imbedded in the yolk, becoming 

 finally very indistinct and hidden from view. At a little later stage the 

 head appears to be divided into three distinct lobes, while the posterior 

 end is somewhat shortened and thickened. 



The subsequent development of the ernbryo I did not observe with 

 sufficient accuracy to say anything of value. Of the interesting phe- 

 nomena accompanying the segmentation of the body, the budding out of 

 the limbs and the revolution of the embryo, I caught only tantalizing 

 glimpses the full import of which 1 was not able to comprehend. It ap- 

 pears in a more advanced stage to lie with the dorsal surface outward 

 against the egg-shell with several of the abdominal segments turned 

 under. 



The embryo when fully developed, occupies the whole of the interior 

 of the egg, without any portion of the body being doubled under. Its 

 ventral thickness is nearly equal to its transverse diameter. Viewed 

 from above (Fig. 21) the division into segments is quite distinct. The 

 head is deeply set into the prothorax, and these two together are equal 

 to nearly one-third the length of the whole. The last two thoracic and first 

 six abdominal segments are nearly equal in length, decreasing gradually 

 in size towards the rear. The seventh segment is larger, bilobed and 

 entirely surrounds the very small eighth segment which bears the conical 

 appendages from which the anal filaments are secreted ; these last do 

 not seem to have appeared as yet. The ninth segment with its append- 

 ages is already seen to be withdrawn, so that the latter appear to arise 

 from the interior of the seventh segment. The body cavity is filled with 

 yolk globules, and the intestinal canal is indistinctly seen. 



Viewed from below, (fig. 22) the head is seen to be produced over the 

 prothorax nearly to the mesothorax, and is closely united to the former. 

 The various limbs are perfectly developed to the smallest hair; the an- 

 tennae are directed backward and extend slightly beyond the bases of 

 the first pair of legs ; the six legs are of nearly equal size, have their 

 bases at the sides, and are all extended backwards and inwards nearly 

 meeting on the median line. The eye spots are very prominent and are 

 situated just above and behind the bases of the antennae, one or both of 

 them are distinctly visible from every point of view. The labium, 

 through which the buccal setae are eventually thrust, is situated be- 

 tween the bases of the anterior feet, and appears to be distinctly bilobed. 

 The buccal setae are seen to be coiled up spirally and nearly vertically 

 on each side of the head with their ends directed towards the internal 

 frame work of the mouth parts. 



