390 Mundy: A Net-building Chironomus Larva. 
To this last group belongs C. puszo, to which I must now 
return. The case (Fig. 1) is found in swift running moorland 
streams, anywhere except in a waterfall, attached to moss or 
rock. It consists of a very compact tube one centimetre long ; 
the free end is surrounded by from four to seven long thin 
arms sticking out like spokes. The whole case is strangely 
suggestive of the common brown Aydra of our ponds. With 
Bre? Ie 
Fiac. II. 
Fic. I.—C. puso, larval case of a full-grown specimen, with two immature 
eases attached at the base. Mag. 2, and natural size. 
Fic. I].—The case of another larva, a closely related species. Mag. ?, 
and natural size. 
head projecting from the tube, lies the larva; and if watched 
closely, it will be seen to dart up one of the arms, carry silken 
threads between this and the next until there is a strong net- 
work formed. This is done between each pair of arms. The 
larva will then retire into its tube once more, and wait while 
the net gets loaded with particles of mud containing desmids, 
diatoms, and other organic matter. Then out it comes again, 
pulls in the web and all it contains, and either devours it, or, 
binding it into a firm mass, adds it to the wall of its house. 
When full grown the larva enlarges the end of its case, and 
after removing the arms, covers it in with a circular disc con- 
taining a small central hole. Then after a rest of twenty hours or 
so the larva changes into a pupa, and out through the central pore 
Naturalist, 
