158 



PSYCHE. 



[October 1S91. 



ofto 



bottom of the brook, and by working 

 my ringers about in the soft mud below 

 them brought them out uninjured. But 

 great was my astonishment on opening 

 one of them to find within a slender, deli- 

 cate, white larva, looking so small in pro- 

 portion to the size of the tube that I could 

 not believe it to be the maker, till re- 

 searches into the other tubes revealed 

 similar occupants in all of 

 them. Fig. 23 represents 

 the mouth parts of one of 

 these larvae, enlarged. The Fi »- 2 3- 

 tube in the centre is the labium (spin- 

 naret) which spins the silken threads, 

 the substance used by all caddis-worms 

 to fasten together the materials of their 

 houses, and fabricate 

 the gratings or disks 

 ■which protect them 

 during pupation. 



These Plectroc- 

 nemia cases occur in 

 colonies, but this 

 ■spring, 1891, I could 

 not find any. They 

 pupate in May, and 

 the pupa may be 

 found in a swelling 

 of a vertical tube 



(fig. 24) . I do not understand what use 

 the larvae make of the lateral chambers. 

 Some in my aquarium, however, only 

 constructed horizontal tubes, in which 

 they lived and transformed. 



Rhyacopiiilidae. In this family 

 the pupa is enclosed in a thin brown 

 leathery cocoon. I have found two 

 species, but I am not sure whether 

 I obtained them in Stony Brook, or in 

 its smaller tributaries. In one of them 

 the case is of no regular shape, being 

 composed of a very few stones, propor- 

 tionately large. 



The other case (fig. 25) is 

 quite peculiar. It is abundant 

 in the Bussey Brook, and I 

 have also found it in Brookline 

 and Dedham. It is about 9 

 mm. long, roundish oblong in Fi e- 2 S- 

 shape, and strongly arched above, and 

 made of coarse sand or gravel. On 

 turning it over, one sees a shelf of fine 

 sand, like the thwart of a boat, across 

 the middle of the case. This dis- 

 appears during pupation. In Bussey 

 Brook I found one pupa on May 9th, 

 1 891, though most of the cases were 

 still occupied by the larvae. 



HALISIDOTA CARYAE. 



BY CAROLINE G. SOULE, BROOKLINE, MASS. 



A mat of eggs was found on the together, about one hundred in number, 



under side of a leaf rather high up in hemispherical, the flat side being on 



a thorn-tree, on June 28th, 1891, the leaf. When found they were of a 



Brookline, Mass. The eggs were close leaden color, and soon each showed a 



