240 BULLETIN OF THE BUREAU OF FISHERIES. 
LIBELLULA PULCHELLA. 
A pair was taken mating on the north shore of pond 4D, and the female deposited 1,500 eggs. These 
eggs were laid July 12; they began hatching July 22, and the hatching was completed by July 28. 
The Egg.—Curiously enough, the egg of this large species is smaller than that of the little Leucor- 
rhinia. It is ellipsoidal in form, measuring 0.48 mm. in length and 0.29 mm. in width. The neck is 
conical, the base nearly twice the height and without any visible segment, but the tip is divided; 
there is no process at the posterior end of the egg. The yolk granules are small and indistinct. 
The Nymph.—This nymph is also just 1 mm. long; the head is one-third wider than long, one- 
fourth the entire length; the abdomen is as wide as the head, with two rows of stout bristles on the 
dorsal surface along either lateral margin; the latero-posterior appendages are very hairy. The antenne 
are long and slender, black at the tips, with a single black band on the basal joint; the legs have black 
and white bands, as shown in the figure; the eyes are straw yellow, with two larger black dots and 
concentric rows of smaller ones; the head between the eyes and whole body is a pale yellow, deepening 
into orange over the gizzard and rectum; there are whitened areas along the sides of the abdomen at 
the posterior margins of segments 4 to 7, with darker areas anterior to them. The base of the antenne 
is whitish, with a black distal band; first joint proximally gray, distally whitish; second joint nearly 
all dark gray, with a narrow, white distal band; third joint dark gray, except the very tip, which is 
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Fios. 41 to 43.—Development of Libellula pulchella; 41, egg; 42, mask of newly hatched nymph; 43, newly hatched nymph. 
whitish. The whole body is transparent and pale white, a little yellowish on the head and at the 
posterior end of the abdomen; the circulatory system is deeper white. 
The Mask.—Mentum three-quarters wider than long, distal margin two and a half times the length 
of the proximal; four sete on the inner surface, near the lateral margin, one proximal to them on the 
margin itself; three mental setz on either side in nearly a straight line; two tiny spines at the center, 
near the distal margin. Lateral lobes one-fourth longer than wide; two sete on the outer margin, near 
the base; two setz on each blade; raptorial seta longer than the movable hook, the latter long and 
narrow; distal margin with six teeth near the outer border, the first two the longest. 
HYBRID BETWEEN LIBELLULA PULCHELLA AND L. LUCTUOSA. 
A male L. pulchella and a female L. Juctuosa were captured mating on the shore of pond 4D July 
9, 1917. The female deposited about roo eggs in a tumbler of water, and these subsequently hatched on 
July 20. 
The Nymph.—This nymph is unlike those of either pulchella or luctuosa, especially in its markings. 
The head is one-third wider than long, and the same width as the abdomen, grayish yellow; the eyes 
are sulphur yellow, with smal! black retinal dots; the rest of the body is pale yellowish, but without 
much color and quite transparent, except along the lateral margins of the abdomen, where each segment 
is dark gray anteriorly and white posteriorly. The whole body is quite hairy, with a row of stout 
