42 E. B. Williamson 



minute flight is at its end, and that he will not see nervosa again for twenty- 

 four hours. 



That the flight is not always confined to the evening however is shown 

 by a note by Klages at Cayenne, French Guiana: "Flies at dusk and at 

 dawn only ; captured in mangrove swamp." Neither is the flight confined to 

 villages, but so far as I have observed numbers are found only about clear- 

 ings or extensive open places, and it is probable that in such places, in 

 proximity to houses, cattle, grasses and freshly hewed timbers, nervosa 

 finds its most abundant food supply. Abundance of food supply may be a 

 factor in determining the number of flights in each twenty-four hour period 

 or the amount of activity during the day. The number of specimens recorded 

 below from Cayenne, where two flights a day were observed, and from 

 Palma Sola, where there w^as a single flight, may possibly indicate a differ- 

 ence in abundance of ncn'osa on the wing and a difl:'erence in the abundance 

 of the food supply. In dark places in the forest with presumably different 

 insect prey one might expect to find nervosa on the wing throughout the 

 day and our observations seem to bear this out. In the forests about Palma 

 Sola, where most wonderful evening flights occurred, the four of us, ranging 

 the forest every day, never saw a nervosa till the evening flight began. At 

 Puerto Berrio, where we did not see nervosa about the town, we took a 

 single male at 9 A. M. one day flying in brush in dark forest about five 

 kilometers from town. J. H. W. noted at Palmdale, Florida: nervosa 

 found in darkest part of cypress grove in creek bottom, flying about bases 

 of trees, or hanging up from three to five feet above the ground. As might 

 be expected from its habits at certain times and places of flying closely about 

 buildings, nervosa occasionally and apparently accidentally, enters such build- 

 ings and is rarely entrapped and captured there. 



At Cristalina, Colombia, about noon one day I saw a Gynacantha fly out 

 from some brush far ahead of me along the creek. It fluttered along in a 

 helpless manner and in attempting to return to the brush, fell into the water 

 from which I picked it. It was a male of G. nerz'osa and on the dorsum of 

 abdominal segments 2 and 3 were six small white eggs. This specimen was 

 sent to Miss Currie at Washington, and the eggs were identified as those 

 of some diptera, apparently a tachinid. There is no previous record of 

 tachinids being parasitic on dragonflies. The same day another nervosa, 

 apparently ill also, was seen fluttering through the brush with hanging 

 abdomen, but I lost sight of it and did not capture it. A male, dlso taken at 

 Cristalina, had in its mouth an insect identified by Mr. McAtee as a cicadellid. 

 I have observed nervosa ovipositing on two occasions. At Alaraquita, 

 Colombia, at the edge of town there was a much used water tap, the overflow 

 water being drained in an artificial ditch with steep dirt sides. About 6 

 P. M. several females Avere observed ovipositing in the soil on the banks of 

 this ditch. In Trinidad a female was taken about noon ovipositing in the 

 damp but hard earth of a wet-weather stream bed in low forest. Stauro- 

 phlebia in larger numbers were ovipositing at the same place. 



Material examined: California (i female. A. N. S.) ; Florida (W. H. 

 Finn. Coll. C. V. Riley, i male. U. S. N. M.), (i female, A. N. S.). 

 Paradise Key, Everglades of Dade Co. (C. A. Mosier, November, 1917, i 



