254 
Psyche 
[June 
searching for an unknown nymph was not worth the reward even 
during the Depression, for the search was never made. Since that 
time few serious attempts to collect the nymph have been made. 
With the exception of a few predominantly tropical genera whose 
ranges extend into extreme southern United States or northern 
Mexico, William sonia is the last genus of Nearctic Odonata for 
which the nymph heretofore has been undescribed. 4 In this paper 
we describe the nymph of Williamsonia lintneri. 
During May for the past three years we have frequently collected 
adults of lintneri in the vicinity of a 40-hectare bog adjacent to 
Ponkapoag Pond in the Blue Hills of eastern Massachusetts (42 0 
I2'N, 71 0 06'W). Our observations of the adults range from 30 
April to 26 May. Although we rarely observed adults in the bog, 
their close association with the woodlands bordering the bog sug- 
gested that the bog, not the pond, was the habitat of the nymph. 
Dredging at several locations within the bog was unsuccessful; how- 
ever, the flushing of a teneral adult from its site of emergence on 
2 May 197° led to the discovery of twelve exuviae and a full grown 
nymph which emerged three hours after its capture. The exuviae 
were shown to be lintneri by comparison to the exuvia of the reared 
nymph. 
The nymph and exuviae were collected adjacent to a log path 
where it crosses an overgrown channel 275 m from the bog margin. 
Here, in contrast to most other parts of the bog, the water is deep 
and remains year-around despite fluctuations created by summertime 
irrigation of a nearby golf course. Highbush blueberry ( Vaccinium 
corymbosum) , swamp laurel ( Kalmia polifolia ), leather leaf ( Cha - 
maedaphne calyculata) , and Atlantic Coast White Cedar ( Chamae - 
cy paris thyoides) form dense thickets on both sides of the channel 
while the channel itself is choked with sphagnum, water arum ( Calla 
palustris), and other water plants. 
All of the exuviae of Williamsonia lintneri were found within 
15 cm of the water surface on emergent vegetation. Over half (7) 
of the exuviae were clustered within a two square meter area where 
young shoots of marsh grass were particularly dense. The teneral 
adults observed in the bog and the emergence of the reared nymph 
suggest that emergence takes place about midday. The fact that all 
but three of the exuviae collected in the area mentioned above were 
collected on or before 3 May indicates that the peak emergence 
4 Dr. Minter J. Westfall, Jr., personal communication. 
