308 
Psyche 
[December 
THE MALE OF THE PARTHENOGENETIC MAY-FLY, 
AMELETUS LUDENS. 
By James G. Needham. 
Cornell University, Ithaca, N. Y. 
This paper is to record the capture of a single adult male 
specimen of Ameletus ludens and to describe it. This sex has 
been sought diligently for more than a dozen years by a number 
of competent students of the Ephemerida, and many hundreds 
of nymphs have been reared in a vain effort to obtain it. Females 
are common enough at Ithaca, N. Y. The nymphs live in the 
pools of the rapid brooks that run down East Hill into Cayuga 
Lake. They poise gracefully on submerged twigs, or dart rapidly 
about over the sandy bottom, and are easily collected in April 
and May. Dr. W. A. Clemens found a single male sub-imago 
and took it into the laboratory but it died before its final moult- 
ing (Canad. Ent. 54: 77-78, 1922). On June 9, 1924, Dr. 0. A. 
Johannsen captured a single adult male in flight by the side of 
Vanishing Brook near his home on Cornell Heights, and turned 
it over to me for study. 
The nymph of this species was briefly described and beauti- 
fully figured by Eaton in his Monograph (Trans. Linn. Soc. 
Lond. (2) 3: 204, pi. 49) in 1885: it v/as doubtfully (and, as we 
now know, incorrectly) referred to the genus Chirotenetes, whose 
nymph was then unknown. The specimen had been collected in 
1874 by Mr. Hubbard at Trenton Falls, N. Y. Female sub- 
imagos taken by Mr. D. B. Young in transformation at Newport, 
N. Y. were described by me in 1905 (N. Y. State Mus. Bull. 
86: 36). 
Males of the other species of Ameletus, all of which come 
from the Rocky Mountains or farther westward, are well known. 
The search for the male of this species was begun by Miss Anna 
H. Morgan. In 1911 she described the adult female (Ann. Ent. 
Soc. Amer. 4: 118) and gave a detailed report of rearings of 
scores of nymphs taken at Ithaca, N. Y., all of which were 
females. She first pointed out that here is a case of probable 
parthenogenesis. Two years later she described and figured the 
