1890.] 131 



anterior, and three filaments on the posterior, segments ; below they are similar, but 

 apparently absent from the eighth segment. As in the larva, the filaments are 

 placed on the anterior part of the segments. 



The ninth segment is smallest, somewhat rounded posteriorly ; from its dorsal 

 surface arise the appendages, wliich are of considerable length (about as long as the 

 segment) ; they are closely approximated, and seen from the side are broad, at first 

 descendent, then a little upturned towards the tips, wliich bear two unequally long 

 bristles ; above they bear several long hairs and an irregular row of minute teeth, 

 together with numerous small sharp points, which are most thickly set near the base. 

 On the under-side of tlie segment are two lobes, whose apices are turned inwards. 



The remarkable dwellings made bj the larvae of M. angustata have 

 been long known, and are figured and described by De Geer. Seen 

 from above the ease is convex, usually very broad in the anterior part? 

 and narrowing in varying degrees towards the posterior extremity ; it 

 is composed of sand-grains, and is moderately smooth along the middle 

 ridge, whereas the side parts are usually loaded with larger stony 

 fragments. Beneath thei'e is visible a tube, slightly tapering and not 

 unlike the cases made by many Leptoceridae, only it is decidedly com- 

 pressed, so that a transverse section is more or less oval ; this tube 

 lies, as it were, in a shallow receptacle, whose sides and fronts usually 

 project far beyond the limits of the tube. In the smaller cases this 

 anterior projecting part is most prominent, and in these also the hind 

 extremity of the tube, seen from beneath, is rounded, the vent ap- 

 parently being on the upper surface. In the larger cases (probably 

 those whose inmates are about to " spin up ") the anterior projection 

 is often nearly absent (but the whole case is very brittle and liable to 

 breakage) ; and behind, the broad parts are produced, and bent in the 

 form of a hood over the end of the tube, the vent of which is placed 

 on the under-side, and consists of a very long slit, whose direction is 

 in the same plane as the long axis of the case. When the case is 

 viewed from the side it appears slightly curved. 



The cases before me vary in length from 16 to 22 mm. ; the 

 greatest breadth is 10 mm., and in the same case the diameter of the 

 tube is 4 mm. at the mouth. The anterior part projects most (4 mm.) 

 in a case whose centre length is 16 mm. 



EXPLANATION OF FIGURES. 



1. Left mandible from above. 5. Antenna. 



2. Eight do. do. 6. Labium and maxillsB. 



3. Left do. from beneath. 7- Labrum. 



4. Eight do. do. 8. Tarsal claw of posterior leg. 



ALL OF LARVA. 



9. Labrum of nymph. 



10. Eight mandible of nymph from beneath. 



11. Apex of abdomen of nymph, from above. 



All the figures drawn with a Zeiss A objective, with the exception of 5 and 8, 

 which are drawn with C. 



Carluke, N.B, : March, 1890. 



