100 [December, 



On the larva and habU.i of Paraponi/x stratiotalis. — It gives me great pleasure 

 to acknowleclgo -with sincere thanks my obligation to Mr. W. C. Boyd, of Cheshunt, 

 for all the trouble he has so kindly taken to furnish me with examples of this curious 

 subaqueous larva, until I have been able to observe its habits -with some degree of 

 completeness. 



On June 10th, 1872, he sent me, in wet moss in a tin box, by post, two cocoons 

 and three larvae ; one of the latter, having died, was submitted to Dr. T. A. Chapman, 

 who examined its structure under the microscope, and very kindly took considerable 

 trouble in making pen and ink sketches of several portions of it — to my great assis- 

 tance in making it out. 



The other examples I figured and described, but was baffled at that lime in fully 

 observing their habits by (as I believe) the carnivorous propensities of sundry leeches 

 and other interlopers, that gained admittance among the leaves of the Anacharis 

 alsinastrum — ^one of the plants on which stratiotalis feeds ; for by the end of the 

 year not a trace of cocoons or larvtB could be found. 



However, on July 21st, 1874, Mr. Boyd was able to send me, by railway, several 

 cocoons and larv£e, as well as a good supply of food, and witli these, having taken 

 more pains, I have been more successful, — carefully removing from their habitat aU 

 creatures that could do them harm, and always straining the water supplied from 

 time to time to make good what had been lost by evaporation. 



Before giving a detailed account of my observations, I had better describe the 

 larva, because the peculiarities of its structure wiU account for the most curious of 

 its habits. 



The larva when full-grown is from six-eighths to seven-eighths incli in length, 

 of cylindrical figure, though tapered a little on the four anterior segments, the head 

 being rather the smallest, and the two hinder segments also a little tapered ; the 

 anterior and anal legs very well developed, the ventral ones moderately so ; the skin 

 is soft and smooth, and furnished with eight rows of flexible branchiae* composed of 

 tufts of six or less slender flesliy filaments of unequal length tapering to rather fine 

 points, and all radiating from a short thick basal stem, and occupying' the positions 

 of the usual warts or spots seen so distinctly in an Agrotis larva, otherwise, to the 

 unassisted eye, they remind one of the spines of some butterfly laiTae. In colour 

 the semi-translucent body is of a very pale tint of olivc-ochreous or of whitish- 

 ochrcous, generally more or less tinged with olive, and marked with a few small 

 purplish freckles ; the alimentary canal is conspicuous, showing through the skin as 

 a broad dorsal stripe of dark grey, or brownish or greenish-grey ; the whitish traeheao 

 can also be partially seen through the skin on each side ; the pale brown head has 

 the lobes delicately outlined with dark brown, the mouth and occUi blackish-brown ; 

 the branchiae dirty whitish-grey ; the spiracles exceedingly small and black, each being 

 situated on the flat centre of a swelling eminence; a small wart-like tubercle near 

 the base of the ventral legs bears a single hair-like filanu'nt. 



On putting the second supply of the larrtc, &c., with the weed, into a glass globe 



* That these are rightly so called, and that they are connected with the respiratory system, 

 I had a. good proof while changing the water of the two first larva; I received : when I put them 

 for a minute or two into a glass of spring water just drawn from a filter, iinincdiately thore 

 appeared a small silvery air bubble at the extreme point of each filament, but when the larvse 

 were returned to the fresh river water these air biibbles soon disappeared. I did not try to make 

 them appear again, as 1 feared the experiment mightfce detrimental to the health of the larvse. 



-w. n. 



