242 



BULLETIN 01^ THE BUREAU OF^ FISHERIES. 



segments, and fades into small, yellow dots on the anterior margins of the fifth, sixth, and seventh, and 

 sometimes the eighth, segment, disappearing entirely on the ninth, and often on the eighth segment. 

 The dorsal appendages on the tenth segment are light brown at the base, yellow at the tip; the lateral 

 and inferior appendages are dark brown. The base of the antennas is yellow distally and proximally 

 with a narrow, black band through the center; first joint dark, with a narrow, distal, white band; 

 second joint with a broader, distal, white band; third joint entirely blackish brown. 



The Mask. — Mentura with the width to the length as 5 to 3 , distal margin two-thirds wider than the 

 proximal; three lateral setae, one marginal seta; three mental setae in a straight line on either side of the 

 center. Lateral lobe with its length to its width as 9 to 7; two marginal setae on the outer border; two 

 setae on the blade of the lobe ; raptorial seta just reaching the tip of the movable hook, the latter long and 

 stout; distal margin crenate, without teeth. 



LEUCORRHINIA INTACTA. 



The sexes remain in union only a short time and usually alight on some convenient weed or bush 

 near the water's edge, where they can be easily secured. When thus captured, the female is ready to 

 lay as soon as taken from the net and will deposit 100 to 200 eggs, the first 50 or 75 coming in a mass 

 stuck together, the others coming singly. Eggs laid July 18 hatched July 30. 



The Egg. — This egg is more nearly spherical than that of Lihellula luctuosa, and has diameters of 

 0.60 mm . and 0.40 mm . , respectively. The neck is wider at the base than it is high, and there is a distinct 

 segmentation at about the center; the tip is not divided, and there is no process on the posterior end of 

 egg. The yolk granules are comparatively large, and the jelly envelope is ragged around the surface of 

 the egg and not smooth, as in other species. 



TheNymph. — Although the imago of Leucorrhinia is much smaller than that of Lihellula luctuosa the 



Figs. 49 to 51. — Development of Leucorrhinia intacta: 49, egg; 50, mask cf newly hatched nymph; 51, newly hatched nymph. 



nymph is considerably larger, measuring 1.20mm. in length; the head is one-third wider than the abdo- 

 men; the front legs are the same length as the body, the others proportionally longer, and all three 

 pairs slender. Both the body and the legs are quite transparent and pale orange yellow in color, the 

 legs and antennae transversely banded with gray and white, the eyes darker orange yellow, the black 

 spots very small. The sides of the head and a wide transverse band across the anterior portion of 

 each abdomen segment are whitish, the posterior margins of the segments are tinged with brown. 

 The bases of the antennae are whitish yellow proximally, with a narrow, gray, distal band; first joint 

 entirely white, a little grayish through the center; second joint with a very narrow proximal band 

 and a wider distal band white, grayish through the center; third joint entirely gray. 



The Mask. — Mentum three times as wide as long; the distal margin twice the length of the proximal; 

 no lateral setae; two marginal setae; three mental setae on either side, not in line, but the proximal one 

 nearest the midline; two stout spines at the center of the distal margin. Lateral lobes with length and 

 width in the proportion of 13 to 9; two setae on the outer margin on either side; two setae on the blade of 

 each lobe; raptorial seta reaching considerably beyond the tip of the movable hook, the latter long 

 and narrow; three small teeth near the outer edge of the distal margin, the central tootli the largest, the 

 rest of the margin smooth. 



