260 NATURAL HISTORY OF AQUATIC INSECTS CH. 



winter in this state. In the month of March I have 

 found in the water cases with perforated ends, and on 

 opening them the pupa was seen. I placed some of 

 these pupae in water, where they lived several days 

 during which time they waved the hinder part of 

 their body to and fro [no doubt for purposes of 

 respiration]. 



" These pupae possess some peculiar features which 

 deserve a moment's attention. The body is white 

 with a citron tinge. On each side there is a narrow 

 black band extending over the four last rings. The 

 tail ends in a small fleshy fork. On the back are 

 bunches of white respiratory filaments, and also four 

 or five brown spots, which under the microscope are 

 seen to be furnished with spines directed backwards. 

 The four wings are plainly to be seen folded and 

 enclosed in the pupal skin, as in Lepidoptera. The 

 head is small in comparison with the body. On each 

 side is a great black eye, and a little below this a beak 

 like that of a parrot. Above this beak may be seen a 

 tuft of hairs which gives the whole head some re- 

 semblance to that of certain Birds, but on close 

 examination it can be made out that what at first 

 sight looked like a beak consists of two hooks [the 

 mandibles], which unite in front, and are crossed 

 at the points. These hooks lie beneath a fleshy 

 projection which carries the tuft of hairs. They are 

 different in shape from any possessed by the larvae. 

 The Caddis-fly has no such organs at all. These are 

 therefore parts peculiar to the pupa ; of what use can 

 they be, seeing that the pupa takes no food ? It 

 is probable, as Vallisnieri supposes, that they are 



