Hudson. — Metamorphosis of the Caddis Fly. 213 



add materially to our information on this subject if they could 

 obtain for examination a number of living caterpillars. These 

 might be obtained by spreading sheets under the tree in which 

 they are supposed to occur, and then beating the foliage. We 

 might then find out if any cases occur of the mycelium develop- 

 ing previous to hybernation. 



Art. XLI. — On the Metamorphosis of the Caddis Fly. 

 By G. V. Hudson. 



[Read before the Wellington Philosophical Society, 2ith February, 1886.J 



Plate IX. 

 The following paper is a short description of the metamorphosis 

 of a species of Caddis Fly (Phryganidas) which I have worked 

 out during the past spring, and which, I believe, differs in several 

 respects from any previously described. The imago is also in- 

 teresting, as it bears such a close resemblance to a Lepidopterous 

 insect ; and, were its preparatory states unknown, it would very 

 probably be catalogued as one of the Tineina. 



Many entomologists are inclined to regard the Phryganidce 

 as a family of the Lepidoptera, and there is no doubt that a 

 very close affinity exists between them ; in fact one family of 

 typical Lepidoptera (the Hydrocampidce) are strictly aquatic in 

 their habits, the larvae constructing cases of duckweed, which 

 they pull after them, holding on to the case inside by two 

 hooks, exactly like the caddis worms ; the pupa state is also 

 passed floating on the surface of the water, and the moths are 

 commonly taken flying over ponds during the summer. 



The larva of this present insect (fig. 1) may be found com- 

 monly in the green, slimy weed floating in large masses on 

 all stagnant waters. Being very small, it is rather diffi- 

 cult to detect, and is best procured by washing a small 

 quantity of the weed in a saucer of water, when the little 

 insects will be at once seen walking about at the bottom. On 

 examination with the microscope, the case will first arrest atten- 

 tion, being of a most unique structure ; its shape is best 

 described as closely resembling that of a minute flask, very 

 much flattened at the lower end, and almost transparent ; its 

 surface is slightly corrugated, and the neck of the flask con- 

 structed of a much denser material than the rest. It is open at 

 both ends, the posterior end being perforated by a long, shallow 

 slit, which extends for nearly the whole width of the case, thus 

 admitting a free circulation of water round the larva, who is 

 also able to turn round and project his head and anterior seg- 

 ments through the lower aperture, thus occupying the reverse 

 position to that shown in the illustration, He is, however, 



