Botany. 645 
24, Empusa rhizospora Thaxter.—“ Neuroptera: Several genera of 
Phryganeide (imagines).” 
25. Empusa gracilis Thaxter.—* Diptera: On very minute gnats.” 
26. Empusa conica Nowakowski.—* Diptera: Imagines of Chiro- 
nomus and other small gnats.” 
27. Massospora cicadina Peck.—“ Hemiptera: Larvie, pup, and 
_ imagines of Cicada septendecem.” 
28. Basidiobolus ranarum Eidam.—* On the excrement of frogs.” 
Collectors may be able to add to the species given above. As 
Mr. Thaxter desires to continue the investigation of the Entomo- 
genous plants of North America, he desires correspondence upon 
this subject, with specimens in quantity. He should be addressed 
at New Haven, Conn. This little group ought now to receive a 
considerable attention at the hands of our botanists.—Charles 
ey. 
A MINIATURE TuMBLE-wEED.—On the great plains of Nebraska, 
from the altitude of two thousand five hundred to three thousand 
feet above sea-level, to and throughout the Rocky Mountain region 
there grows the very pretty little aster-like plant known as Town- 
sendia sericea Hook. It blooms in early spring, and its pretty, 
almost sessile, heads of numerous flowers nearly cover the plant 
itself, so that one sees little more than a compound rosette of yellow 
and delicate pink close upon the ground. 
After blossoming, the bracts of the involucer remain for a consider- 
able time widely opened, but when the achenes are ripe the involucer ” 
closes and forces out the mass of achenes, with their abundant long, 
white pappus and effete corolla tubes. This expulsion was observed 
in 
to take place, in one instance, in a plant grown in my laboratory 
with such force as to suddenly throw the mass of achenes and pap- 
pus out free from the involucer. I suppose that the spreading of 
the pappus has also much to do with freeing the achenial mass from 
the involucers. Possibly the pappus and involucers act together. 
a The achenes are pretty well covered with long twisted and bent 
yan ” hairs, asis common in this and many allied genera.’ 
sshown b ie, in hi ron “ Achenial Hairs 
and Fibres of Diaan gy meae ren eeta Vol. XVII., p. 81; 
and also “ Achenial Hairs of Townsendia.” Ibid., p. 1102. 
