(.32 SAMUEL II. SCUDDEE ON THE 



such a dcposil as thai in which these remains were found." In this communication, 

 finding among the specimens I examined none with any lateral appendages, I concluded 

 thai the figures which had been given were inaccurate in that particular, a conclusion 

 based, as will be seen, on insufficient material. 



A few years later, Dr. A. S. Packard published a short note upon them, in which he 

 expressed the opinion that they were "aquatic coleopterous larvae, belonging- perhaps 

 near the family Heteroceridae." 



It will thus be seen that some difference of opinion has been expressed concerning 

 the affinities of these fossils, though they have uniformly been considered larvae, and as 

 belonging either to Neuroptera or Coleoptera. 



Having recently been able through the kindness of Professors Emerson and Hitch- 

 cock to examine the considerable collection of these remains in the cabinets of Amherst 

 College, and by favor of Professor Marsh to study all the specimens in the Yale Muse- 

 um, I have examined with care some hundreds of these larvae, and reviewed the whole 

 subject anew r . Notwithstanding the considerable differences which show themselves, I 

 am strongly convinced that all the specimens I have studied belong to a single species. 

 differing somewhat in structure from what I formerly believed, and whose affinities are 

 pretty clearly different from what I formerly supposed, several new features, not before 

 observed, being now apparent. This point, however, will he discussed after the struct- 

 ure has been set forth in full. 



The body is composed of thirteen apparent segments, of which the head forms one, 

 and three are differentiated, sometimes very obscurely, as thoracic. The statement that 

 the head forms but a single segment is at variance with my former conclusion, for the 

 two segments of the description then given by me form together what I now look upon 

 as the head. There are doubtless a good many specimens which lend color to my former 

 conclusion, and I reproduce upon the plate (fig. 3), a copy of a drawing made fifteen or 

 more years ago of what I then considered the first three segments of the body. A sim- 

 ilar development of the first segment may be seen in fig. 13, and to a much less extent 

 in fig. 9. Whether these lateral anterior lobes of the head, always separated from it by 

 a more or less marked suture, are inferior appendages showing only when projected for- 

 ward, can hardly be determined, but this seems the most probable explanation. The de- 

 cided differentiation of the thoracic segments in certain individuals (see figs. 1, 5, 11 

 for example) leaves no room for doubt that the smaller segment in front of them, usu- 

 ally single, at other times apparently double, represents the head. 



The head then is a rounded segment, usually a little broader at base than in the middle 

 (see especially figs. 12, 16) and slightly broader than long, the front well rounded. 

 It is generally about as large as the hindmost segment of the body, but occasionally is 

 larger than it where the final segment appears but partially extended, and in a few in- 

 stances is much larger; it is then also out of all due proportion to the segments behind 

 it, as in fig. 10, where it does not appear to be crushed and unnaturally expanded, but 

 rather as if the lower appendages of the head, forming in other cases the protruded an- 

 terior lobes, had been laterally spread out and lay beside the head, of which, as in the 

 other case, they seem at first sight to form an integral part. That this is the correct view 

 is the more probable because, when the surface is not absolutely Hat (as may be the case 



