1 8 E. B. Williamson 



At Puerto Barrios the large palm swamp adjoining the town had been 

 cut off prior to 1909 for some distance back from the coast, and over this 

 area in May and June, as darkness came on in the evenings and as darkness 

 gave way to light in the mornings, scptUna came from the nearby forest to 

 dart back and forth, high in the air, or near the ground, in countless thous- 

 ands. But because of their erratic Hight the collector found himself netting 

 only an occasional specimen where dozens were apparently awaiting the 

 sweep of the net. At Bolivar the following note: "This species the most 

 erratic flier 1 have ever seen, and possibly the most difficult to catch. .Along 

 road after sunset. Few flying where there were many last evening. Began 

 flying at 5 :45 p. m."' At Puerto Berrio, "Flying along the railroad track 

 below the hotel about 6:10 p. m., — almost dark." At Cienega, "A male flew 

 into a lighted car at railroad station at 7:15 p. m. — dark outside.'' At Palma 

 Sola, "Flies along railroad track and in clearings in the woods just after 

 sundown; very erratic especially in clearings; in town along railroad tracks 

 associated with Gynacantha nervosa." At Tachira, "Flying along railroad 

 after sundown." 



Their erratic flight is due to sudden darts after their prey which they 

 detect at some distance. In clearings and along roads or trails the sky above 

 them is a clear bright field and I have often seen septiuia rise several feet to 

 seize its prey. In fact, so far as I can recall, they always strike from below. 

 I have never found them flyine in the mornings except at Puerto Barrios. 

 It seems improbable that early evening and early morning flying occur gen- 

 erally, for the usual great differences in day and night temperatures might 

 be expected to prevent this. 



In my field notes the reference to septUna as the most erratic flier I have 

 ever known should doubtless be modified. Other species of Triacanthagyna 

 are probably as swift and erratic, and, after repeated observations one after- 

 noon, I give the palm for abrupt and erratic and perfectly controlled flight, 

 among all the dragonflies I know, to Tlwlyiiiis citriita. 



Material examined: Mexico (A. N. S. i male, i female; U. S. N. M. i 

 female); Guatemala ( \'an. Patten, i female M. C. Z.). Puerto Barrios 

 (May 25, 26. 28, and 30, and June 23. 1909, t6 males, 12 females E. B. \V.). 

 Santa Tomas (May 29, 1909, i male, E. B. W.), San FeHpe (Hay and 

 Maxon, February 22, 23, 1905, i male, i female, U. S. N. M.) ; Costa Rica, 

 Guapiles (P. P. C, July 13, 1915. i female, A. N. S. ) ; Colombia, Santa 

 Marta (December 16. 1916, 2 females, E. B. W.), Bonda, Dept. Magdalena, 

 250 feet (H. H. Smith, July and August, 2 males, i female, Carn. Mus.), 

 Bolivar, near Santa Marta (December 21, 24, 25 and 26, 5 males, 3 females, 

 E. B. W.), Cienega, Dept. ]\Iagdalena (February 26, 1917, i male. E. B. W.), 

 Rio Frio, Dept. 'Magdalena (January 7. 1917, i male. E. B. W. ), Rio Xeuvo. 

 Dept. Bolivar, on Magdalena River, between Magangue and El Banco (Jan- 

 uary 22, 1917, I female. E. B. W.), Puerto Berrio. Dept. Antioquia (Jan- 

 uary 31 and February 21, 1917. 2 females, E. B. W.) ; Bcuador^ (F. Campos 

 R., I female, Cornell), Guayaquil (F. Campos R., 4 males, 2 females, A. 

 X. S., I female, Ris). El Salado (F. Campos R., i male, i female, A. N. S.), 

 S. Rafael (F. Campos R., i female. A. N. S.), Babahayo (F. Campos R., 



