DRAGONFLIES AND DAMSELFLIES IN PONDFISH CULTURE. 187 
each of them contains enough aquatic plants to make it very attractive to both dragon- 
flies and damselflies. The distribution of fish and vegetation in and around these 
ponds is shown in the two tables which follow. 
It may be noted that a heavy fringe of common crex grass, Carex stricta, has been 
planted at the water’s edge around each of the ponds in order to prevent wave washing 
(Pl. LXVII, fig. 1). Ponds 1, 2, 3, and 7 are partially covered, at the proper season 
of the year, with a thick scum composed of the pollen of Philotria blossoms; ponds 
4 and 8 show this scum in much smaller quantity, while it has not as yet appeared 
in the other ponds. 
Along the north embankment of ponds 1, 2, 3 and 4 runs a cinder road (Pl. LXVII, 
fig. 2), to the north of which, away from the ponds, the land rises rapidly and was 
covered during the two summers of the present investigation with a heavy growth of 
grass, in which the dragonflies were accustomed to roost at night. This upland grass 
field up to the time of mowing was literally filled with odonate imagos, Libellula luctuosa 
being most numerous. Females could be found there at any time of day, and toward 
night or early in the morning, especially after a heavy dew, both sexes were present in 
large numbers. The alge, pondweed, and rushes around these ponds furnish exactly 
the conditions favorable for odonate propagation, and, taken in connection with this 
ideal roosting place, with the constant supply of fresh water, and with the abundance 
of food, they present an exceptionally fine breeding ground for dragonflies and damsel- 
flies. This is shown not only by the comparatively large number of species found 
around these ponds but also by the extraordinary abundance of some of them. 
To the south of the ponds along the railroad track is a ditch which always contains 
more or less water and which proves a favorite haunt for Plathemis lydia, Anax junius, 
Libellula pulchella, and Pachydiplax longipennis. There is a fringe of willows along 
the river bank opposite the ponds, and the slope of the terrace to the north of the 
dwelling houses beyond the highway is also wooded, but there are no trees or bushes 
anywhere in the vicinity of the ponds themselves. 
The plankton of the ponds is very rich in entomostraca and other forms of life, 
and the water plants are covered with snails and insect larve of all kinds, furnishing a 
good food supply. 
FisH DISTRIBUTION IN PoNDS OF SERIES D, Farrport, Iowa, 1916. 
Pond numbers. 
Species. 
I 2 3 4 5 6 7 8 9 
Micropterus salmoides: Largemouth black bass, adults............... Xx 
Micropterus salmoides: Largemouth black bass, yearlings........... Xx 
Micropterus dolomieu: Smallmouth black bass, adults...............J.....- 
Pomoxis sparoides: Black crappie, adults.................. cae x 
Pomoxis sparoides: Black crappie, yearlings... 
Lepomisincisor: Bluegill, adults............... : 
Lepomisincisor: Bluegill, 2-year olds, ...... 2.2.2.0... 250000222 c eee x 
Ictiobuscyprinella: Red-mouth buffalofish, adults............... ; 
Ictiobus bubalus: Smallmouth buffalofish, adults...................]...... 
Ictiobus bubalus: Smallmouth buffalofish, yearlings.............. 
Ictiobus bubalus: Smallmouth buffalofish, fry.................0... 
Lepomis gibbosus: Common sunfish, adults....... 
Lepomiseuryorus: Wide-eared sunfish, adults... . 
Cheenobryttus gulosus: Warmouth bass, adults. .. 
Ictalurus punctatus; Channel catfish, adults 
Ictalurus punctatus: Channel catfish, fry 
