NORrH AMKRICAN ODONATA. 259 



Reddisb browu. Thorax each side with two white or yellow stripes; a yellow 

 spot on each side of 2-10. Wing-bases yellowish ; the following reddish brown: 

 the nodal spot, a pterostigmal band, sometimes the apices of all four, sometimes 

 a small anal spot on hind wings; the following blackish brown: on the front 

 wings the apical half of the median space and the first few cells between the sectors 

 of the arculus, on the hind wings the basal stripe to the outer angle of the tri- 

 angle. Pterostigma reddish brown. 



Abd. % 26-29, ? 25-28. H. w. % 35-37, 9 34-38. 



Fairly abundant around Phila., May 17 — July 22. 

 Maine to Florida, west to Michigan and Texas. 



53. Liibellula pulcliella Drury. 



L. p. Drury, 111. Exot. Ent. i, p. 115, pi. 48, fig. 5, 1770. Hagen, Syn. Neur. 

 N. A., p. 153, 1861. 



Blackish brown. Thorax each side with two stripes, a stripe on each side of 

 1-9 or 10, yellow. Wings with a longitudinal basal stripe between subcosta and 

 postcosta out to beyond the triangle, a large nodal spot, and apex, blackish browu. 

 Pterostigma blackish brown. % . Wings with milky spots adjacent to dark brown 

 ones; abdomen pruinose in old males. 



Abd. % 32-35, 9 30-33. H. w. % 40-43, 9 41-43. 



Very abundant around Phila., May 30— Sept. 14; in copula or 

 ovipositing June 18, 22, July 2, 20, 23, Aug. 16, 18. 



Quebec to Georgia, west to Utah and Texas ; California (A. E. S.). 

 N. B.— The females of L. pulchella and Plathemis trimaculata resemble each 

 other, and are often confounded. The former is to be recognized by its larger 

 size, its larger yellow spots on the sides of the abdomen forming a band, and by 

 its relatively shorter pterostigma, which is three-eighths as long as the first post- 

 cubital space, while that of trimaculata is one-half as long as that space. 



31. Plathemis Hagen. 



Hagen, Syn. Neur. N. A., p. 149. 1861. Kirby, Trans. Zool. Soc. Loud, xii, p. 



287, 1889, 



54o Plathemis trimaculata De Geer. 



LibeUula t. De Geer, Mem. iii, p. 556, tab. 26. fig. 2, 1773. P. t. Hagen, Syn. 

 Neur. N. A., p. 149, 1861. LibeUula lydia Drury, 111. Exot. Ent. i, p. 112, pi. xlvii, 

 fig. 4, 1770. Drury's name has a priority of three years, but as trimaculata is 

 widely known as the name of this species, no change is here made. 



Brown. Thorax each side with two white stripes each terminated below by a 

 yellow spot ; a white or yellow spot each side of 2-9. 



'J, . Wings with a longitudinal basal stripe between subcosta and postcosta as 

 far as the triangle and clearer in the middle, a band across the wing from nodus 

 to pterostigma, and sometimes the extreme apex, blackish brown ; a chalky-white 

 cloud below the basal stripe. Thorax (partly) and abdomen white pruinose in 

 older males. 



9. Wings with a basal stripe as in ^ , a nodal patch reaching half across the 

 wing and apex, blackish brown ; 8 perfoliate. See note to LibeUula pulchella 



Abd. % 25.5-30, 9 23-24. H. w. % 31-34.5, 9 32-33.5. 



TRANS. AM. ENT. SOC. XX. SEPTEMBER, 1893. 



