SCUDDEK ON TERTIAEY INSECTS. 543 



meutionecl by writers, and Sir Charles Lyell figures them iii his Manual. 

 Oustalet, in his recent treatise on tlie fossil insects of Auvergne, describes 

 two forms,* one from Clermond, and the other from St. G6rand, which, 

 lie distinguishes under the names Fhryganea corentina and P. gerandina, 

 principally from their difference in size and strength, and a distinction 

 in the minute shells — species of Paludina — of which the cases are com- 

 posed. One of them, however, probably the former, was previously 

 named by Giebelf Indiisia tahulata, a generic name which it would 

 l^erhaps be well to employ for the cases of extinct Fhryganidw, until they 

 can reasonably be referred to particular genera. 



During the past season. Dr. A. C. Peale, in his explorations under 

 the Survey, discovered on the west side of Green Eiver, Wyoming Terri- 

 tory, at the mouth of Lead Creek, in deposits which he considers as 

 IDrobably belonging to the Upper Green Eiver Group, or possibly to the 

 lower part of the Bridger Group beds of limestone, the upper floor of 

 which is completely covered with petrified cases of caddis-flies, all belong- 

 ing to a single species, which may bear the name we have applied to it 

 above. They vary from 14 to lO™"' in length, from 4 to 5"^"^ in diameter 

 at their open anterior extremity, and from 3 to 3.2™°^ at their posterior 

 end, the thickness of the walls being about 0.75™"^. As will be seen by 

 these measurements, the cases are a little larger at their mouth, but 

 otherwise they are cylindrical, taper with perfect regularity, and are 

 straight, not slightly curved, as in many Phryganid cases. They are 

 completely covered with minute, rounded, water- worn pebbles, apparently 

 of quartz, generally subspherical or ovate, and varying from one-third to 

 two-thirds of a millimeter in mean diameter ; they thus give the cases 

 a granulated appearance. Nearly all the cases are filled with calcareous 

 material, but some are empty for a short distance from their mouth, 

 and in one case the inner linings of this part of the case has a coating 

 of minuter calcareous particles, evidently deposited therein after the 

 case was vacated. As the present thickness of the walls indicates (as 

 also the size of the attached pebbles), the silken interior lining of the 

 case must have been very stout. This follows also from the appearance 

 of one or two which have been crushed ; for they have yielded along longi- 

 tudinal lines, indicating a parchment-like rigidity in the entire shell. In 

 one of the specimens, the outer coating of heavier pebbles has in some 

 way been removed by weathering, and has left a scabrous surface, ap- 

 parently produced by minute, hard grains entangled. in the fibrous 

 meshes of the web j it still, however, retains its cylindrical form. 



The size of the case, its form, and the material from which it is con- 

 structed seem to indicate that it belonged to some genus of Limnophi- 

 lidce near AnaboUa. 



* Bibl. Ecole Haut. Etudes ; Sc. Nat. iv, art. 7, pp. 101-102. 

 t Ins. der Vorw. 269. 



