■ I.] 



29 



meso-thorax about same breadth as pro-thorax, transverse; meta-thorax 

 soft. First abdominal segment with a large dorsal and smaller lateral 

 protuberances ;* the remaining segments cylindrical, gradually diminish- 

 ing in size to the anal extremity ; the terminal segment having two 

 small processes bearing the usual booklets, and provided with a few 

 very long hairs. The respiratory filaments appear to be present only 

 on the first three abdominal segments on the dorsal and ventral surfaces 

 towards the sides, those on the back being turned inwards and almost 

 meeting ; they are flagellate in form, consisting of three to five long 

 threads attached to a short and broad foot-stalk. The legs have a few 

 very long hairs. 



The larva is pale green : head above olivaceous-brown, wnth two 

 pale lines, which converge, forming a sort of U, the eyes are very con- 

 spicuous, being placed in large pale patches ; pronotum beautifully 

 marked with thickly-set, small, round, dark brown or blackish dots, 



I" which become larger and less thickly set in the posterior part ; meso- 

 iiotum greenish -fuscous, with two darker points. Legs clear yellowish, 

 darker about the joints. Anal booklets also yellowish. 



These larv« are almost always found at the bottom, and they do 

 not appear to feed on water-weeds : Mr. McLachlan suggests that, in 

 all probability, their food consists of minute Desmids and Diatoms 

 that must abound in the localities where they occur. 



The cases are cylindrical tubes, 7 to 9 mm. in length, much curved 



and greatly attenuated to the tail-end, formed of fine sand-grains, 



covering an inner silken tube, and usually very black in colour. 



'^* When about to change, the larva attaches the case by a silken band, 



4 spun round the mouth-end, to the root-fibres, &c., of aquatic weeds, 



I and closes it with a somewhat convex membrane, in which there is an 

 excentric slit. The nymph-state appears to extend over a period of 

 about four weeks. 



;ref 



Carluke, N.B. : 



lOth June, 1884. 



[Dr. Brauer was so kind as to send me one of the original larvae 

 (with its case) obtained by Yon Frauenf eld ; it agrees in every respect 

 with those found by Mr. Morton.— E. McL.] 



* With regard to these protuberances, which are always visible in examples in alcohol, they 

 would appear to be capable of withdrawal and inflation in the hvmg larva. Mr. King directed 



my attention to this, and I subsequently confirmed it. 



