Clarke.] 



70 



[Mfiy 24, 



internal lining of silk, which at the lower end is separated from 

 the side of the tube and seems to be 

 slightly drawn together, so that it is diffi- 

 cult to push anything through from the 

 outside, though a small stick can be easily 

 thrust through from the inside. At the 

 upper end of the case, just above the head 

 of the pupa, is a perforated disk. I col- 

 lected a number of tubes on May 13th, and 

 found that nearly all the larvae had pu- 

 pated. 



On June 28th, I found in the same place 

 the cases of the young larva (fig. 5), 

 shaped like those of the adult, with the 

 Fig. 4. same vertical chimney and lateral chambers. 



In these the height of the shaft varied from one-half to seven- 

 eighths of an inch, and the length of the side pieces from one 

 quarter to nearly one-half of an inch. 



Larvae collected in November were almost 

 seven-eighths of an inch long. The body of 

 the larva is slender, and somewhat flattened, 

 and ends in a pair of long anal crotchets. 

 There are no external respiratory filaments. 

 The small head is yellow, the. thorax white, 

 and the abdomen lavender-blue. The young 

 Fio-. 5. larvae are white. 



A microscope shows the long spinneret of the larva, and the 

 little brushes of hairs on the mouth parts. The legs are very 

 short, and the last joint of the first pair is flattened and edged 

 with a thick brush of hairs. The hairs on the other legs are 

 short and stiff. 



The pupa is nearly half an inch long, with a light green abdo- 

 men and blackish-gray wings. The abdomen is kept in constant 

 motion, and has three pairs of gills upon each side ; the first and 

 second pair are forked. 



I have kept the larvae all winter in confinement, hoping to see 

 them build, but they merely made a rough, horizontal tube, show- 

 ing no disposition to construct a vertical chimney. The tubes 

 were attached to the bottom of the vessel and left unfinished 

 beneath. 



