53 



two or three smart strokes of its tail send it to a safer region. 

 At anotlier time it will be singularly apathetic, and may be 

 touched lightly without alarming it. I have fed it every day 

 with two or three house flies, securino; them bv the leo;s with 

 forceps, and holding them to the larva ; it will generally seize 

 them at once, but if the position in which they are presented 

 allows them to touch the larva before it has seized them, the 

 larva will back off from them with a stroke or two of the tail. 

 I have known it to seize a fly by a leg or a wing and hold it, 

 but it prefers to take them by the body, and once secured there 

 is no escape. 



An extended description is not desirable in this place, but a 

 short synopsis of its characteristics will enable any observer to 

 recognize the larva. 



Each of the two specimens that I have mentioned was about 

 thirty-five millimetres long, rather slender, narrowing very 

 moderately from the middle of the body to the head, and more 

 strongly in the opposite direction to a narrow final segment. 

 The head is large and prominent, the body moderately flattened 

 and somewhat appressed. The mandibles are rather large and 

 strong, nearly straight and strongly toothed on the inner edge 

 at the tip. The mandibles are usually widely extended when 

 the larva is walkino; about at the bottom of the vessel. On 

 each side of each segment after the thoracic one, there is a 

 slender whitish filament, which is a little longer than the body 

 is wide at its widest part. From the posterior edge of the 

 terminal segment there arise two filaments, contiguous at their 

 base, long, blackish, very contractile, and rather thicker than 

 those of the sides. These filaments are undoubtedly respira- 

 tory organs, and are usually directed upwards, so that their 

 tips reach the surface of the water. There is a long, stout, 

 bifurcated pro-leg just beneath these filaments. The color of 

 the head is chestnut brown ; that of tlie body rather light 

 brown, with a black interrupted medio-dorsal line, and, on each 

 side, a much narrower and more obscure similar line. The 

 legs are rather stout, of moderate length, and honey yellow. 



Henry L. Moody. 



