146 Journal New York Entomological Society, t^'o'- >^^ii- 



Cascadilla Creek it seems evident that its distribution is extremely 

 local. 



Larval Habits. — During the spring and early summer of 1913 

 search was again made for the larvae but none were found until July 

 20. The cases found at this time were entirely different from those 

 taken from the same locality in August, 1913. It was later discovered 

 that the 1911 larvae were in pupa cases. 



The larval cover, pi. 2, fig. 4, is a thin, flexible sheet of silk, 

 irregular in outline and closely cemented to its support throughout 

 the greater extent of its margin. At two or three places it is not 

 attached, these openings allowing free circulation of water. 



The size of the silk sheets, pi. 2, fig. 4, when first found varied 

 from one half inch to more than two inches in length and were about 

 one fourth inch in width. Some were simple, others showed irregu- 

 lar branches. On July 26 some sheets were five inches long and 

 more than an inch wide. On the latter date two pupal cases, the first 

 of the season, were found. These contained larvae which had not 

 started their inner cocoons. On July 30 larvre were still more com- 

 mon than pupre but by the 5th of August almost all had pupated. 



It is probable that there are two broods in a single season for in 

 the bottles containing pupre and pupal cases were discovered several 

 small larvae of the same species which ranged from 3 to 6 mm. in 

 length. These larvae were not seen when collected, but probably 

 were picked up with tlie pupal cases. Additional evidence of an 

 earlier brood was given by the occurrence of several adults among the 

 insects caught in a traplantern in June. 



Food of the Larvae. — The organic contents of the stomachs con- 

 sisted entirely of algjc. Most abundant were Sccncdcsmus and frag- 

 ments of filamentous Chlorophyceae; diatoms and Pcdiastrum were 

 also found, as well as a large amount of silt. It is surprising to note 

 that in the stomachs the green algae were in greater abundance than 

 the diatoms, although in the ooze which surrounded the larvae diatoms 

 greatly outnumbered the green algae. 



Pupal Habits. — Shortly before the time of pupation the silk sheets 

 are removed and a cover of an entirely different nature is formed. 

 This removal of the silk sheets leaves clean scars on the rocks, pi. 2, 

 fig. 5, which in color, contrast strongly with the surrounding diatom- 

 aceous coating. Within these scars, sometimes in the center, some- 



