T. D. A. CocJcerell — Descriptions of Tertiary Insects. 387 



Apparently the genus must be referred to the Odontoceridse, 

 but Mr. Banks intimates that this is hardly a natural family, 

 but "a sort of waste-basket" for things hardly fitting into Seri- 



Fig. 12. 



Fig. 12. Phenacopsyche vexans Ckll. Diagram of venation. 



costomatidse, and without the necessary characters of Leptoce- 

 riclse, Rhyacophilidse, or Hydropsychidse. 



Hob. — Miocene shales of Florissant, 1908 (Station 13 B, 

 Geo. N. Roliwer). 



Hydropsyche scudderi sp. nov. 



Larva in general similar to that of Hydropsyche sp., figured 

 in Bull. 47, New York State Museum (1901), plate 15, f. 3, but 

 much longer (length about 31 mm ), though not broader (width 

 of thorax about 3 mm ), and with the thoracic plates much more 

 nearly equal in size, being, in lateral view, about as deep as long. 

 Head and thoracic plates strongly chitinized, of the usual 

 rather dark reddish brown color ; head 3 mm long and 2 deep, 

 apparently quite normal ; abdomen visible only as a faintly 

 darker shade, of about the same width as the thorax, having 

 slight indications of dark transverse and longitudinal markings. 

 On one specimen indications of the branched gills, yellowish 

 in color, can be seen on the first three segments. The caudal 

 end is slender and produced, the caudal legs provided with the 

 usual spreading bunches of hair. No indication of any case. 



There are two good specimens before me, one showing the 

 dorsal, the other the lateral aspect. Many others have been 

 found ; those in which the abdomen cannot be clearly seen are 

 curiously similar to Scudder's Planocephcdus aselloides. 



Hob. — Miocene shales of Florissant. 



Scudder is no doubt correct in assuming that the Hydropsy- 

 chiclse of Lake Florissant did not breed in the lake, but in the 

 small streams running into it. During the volcanic eruptions 

 these streams may have been so heated that the larvae were 

 killed and then washed into the lake. 



University of Colorado, Dec. 2, 1908. 



