258 [April, 



front margin is deep black ; the eyes are large and deep black, scarcely elevated above 

 the surface of the head, and, imder a two-thirds of an inch object-glass, shew no trace 

 of disintegration. The labrum is rounded on itk edge ; the maxillaa are furnished 

 with three-jointed palpi, which are short and gradually diminishing in thickness 

 from base to apex ; the mandibles I cannot dif tinguish ; the labium is obtusely 

 conical, and with a deep black annulus at its base The pronotiun is transverse ; its 

 anterior edge straight, with the angles not prodiiced, but furnished with isolated 

 black hairs ; there is a longitudinal median line, and a transverse line broadly con- 

 cave dividing the pronotum into two unequal transverse portions ; the colour is 

 obscure yellowish with a black line posteriorly. The mesonotum is much broader, 

 straight in front, rounded behind, pale whitish-green, with a yellow dorsal plate 

 divided by tliree longitudinal lines, so that its posterior edge is trilobate ; the side- 

 pieces on which the legs are placed have a deep black irregular marking ; on the 

 surface are a few long black hairs somewhat arranged in fan-shaped series. The 

 metanotum is narrow and transverse, pale-green, the side-pieces marked as in the 

 mesonotum : the metasternum has a fringe of long black hairs on each side of its 

 anterior edge. The legs ai*e yellow, marked with a black line on each edge : the 

 anterior pair very short, the two other pairs long and equal ; in the anterior pair all 

 the joints are short, the femora being very broad and compressed ; in the other pairs 

 the joints are longer, the trochanters one-third the length of the femora, these latter 

 slightly dilated ; the tibiae not longer than the trochanters, with an unequal pair 

 of testaceous spurs at the end ; the one-jointed tarsus rather longer than the tibia, 

 spurred at the end, and provided with a single piceous curved claw nearly as long as 

 the tarsus itself. The first abdominal segment has no appreciable humps. The 

 whole abdomen is nearly parallel on the sides, and of a very pale green ; the branchial 

 filaments short and isolated, or at the most, two only are placed together (but they 

 are somewhat indistinct in the dead larva) ; the terminal segment is yellowish, with 

 three tufts of long black hairs, one in the middle, and one on each side on a dilatation 

 which carries the anal claws, these latter being short, brown, each strongly directed 

 hack upon its basal support, and witli a very small tooth exteriorly placed upon the 

 (i;c'niculation. 



The foregoing description is made from microscopical examinations. The living 

 i-i'-ra was plainly discernible within its sub-diaphanous case when in tlie water, and 

 wris almost constantly in rather violent motion of a serpentine nature, but without, 

 of course, changing the position of the case, which was attaclied by a filament at the 

 smaller end to the plants among which it fed. This motion, no doubt, maybe looked 

 upon as connected with its breathing apparatus, and is probably rendered necessary 

 both by the paucity of the external branchial apparatus and by the fact that the larva 

 inhabits slowly flowing, and hence only slightly aerated, water. 



Tliis larva bears considerable affinity to that of Oligoplectrum maculatum, as 

 described and figured by Pictct. 



It appears to me that concerning both this and almost all other Trichopterous 

 larvae, there is a gap in the observations of habits remaining to be filled through 

 more extensive study. It is very evident that, although a larva adds to the length 

 and breadth of its case at the larger end as necessity requires, there must, in many 

 instances, be periods in its life when the case must be wholly modified (perhaps 

 abandoned) ; for even the smaller end of the case of a well-grown larva is infinitely 



