DRAGONI^UES AND DAMSEIvFUES IN PONDI^ISH CULTURE. 



245 



cylindrical, covered with short and straight spines or setae. All the leg joints, including the coxae, 

 are sparsely armed with setae; and there is a row of setae also along the dorsal surface of the abdomen 

 close to the lateral margin. The color is a uniform, creamy white, except the three dark bands on the 

 antennae and a narrow band on each femur and tibia of the legs. 



The Mask. — Mentum triangular, one-half wider than long; distal margin twice the length of the proxi- 

 mal; one mental seta on either side, one lateral seta at the base of each lobe, two marginal setae; a row of 

 nine small spines just behind the distal margin. Lateral lobes twice as long as wide, with one marginal 

 seta and two raptorial setae; movable hook long and stout; an accessory spine just outside the base of the 

 distal raptorial seta. 



Figs. 58 to 60.— Development of Enallagma hageni: 58, egg; 59, mask of newly hatched nymph; 60, newly hatched nymph. 



ENALLAGMA SIGNATUM. 



These eggs were obtained from pond-lily leaves on July 28, 1917, and began to hatch 18 days later, 

 tJie period of incubation being again unknown. 



The Egg. — The eggs are considerably like those of E. hageni, but they were arranged very differ- 

 ently in the tissues of the leaf. Those of hageni were inserted without any definite order anywhere 

 in the leaf; these were arranged in a semicircle on the underside of the leaf around some convenient hole 

 or close to the margin. The female evidently thrust her abdomen down through the hole or down over 

 the edge of the leaf and, reaching as far as she could, inserted the eggs into the leaf. 



The Nymph. — ^The nymph is just i mm. long, exclusive of the caudal gills; head wider than long, 

 the two diameters in the proportion of 7 to 5, the anterior and posterior margins both strongly convex; 

 thorax shorter than the head and two-thirds as wide; abdomen the same width as the thorax and taper- 

 ing gradually backward; caudal gills short and slender; legs also comparatively short and slender, 

 the posterior pair not reaching the center of the caudal gills; claws short and stout. The antennae are 

 long and stout; the eyes at the center of the lateral margins project strongly. There are no setae 

 on the dorsal surface of the head, on the thorax, or on the coxae of the legs; there is a single seta on the 

 center of each abdominal segment near the lateral margin on each side ; and the setae on the legs and 

 146954°— 20 5 



