OF WASHINGTON. 9 
can easily free themselves. In the case of Cenchrus echinatus, 
however, the spines or barbs along the involucres of the ripen- 
ing seeds point downwards and form a perfect and infallible 
trap for any insect that flies against the ears of the grass. 
In spite of the fact that even in a very small area untold 
thousands of insects are thus captured every night or day by 
this Cenchrus echinatus, there appears to be no'ground for be- 
lieving that the plant derives any benefit from their capture, 
and the phenomenon must be classed among the numerous in- 
stances of plants accidentally capturing and killing insects. 1 
In discussion, Mr. Morris observed that an allied species of 
grass, Cenchrus tribuloides, the common sand burr, had been 
found by him along the shores of Lake Michigan in"northwestern 
Indiana and northeastern Illinois with certain species of flies 
caught in its spines. Mr. Schwarz said that Elaterid beetles 
caught by the grass live for three or four days andTthen decay. 
He had never seen any insects caught by the sand burr in Florida. 
The subject of insects impaled on thorns was then brought 
up, Mr. Schwarz maintaining that such cases are the work of 
shrikes and do not result from accident. Mr. Hay stated that 
he had found insects in central Indiana mostly grasshoppers 
impaled upon the barbs of barbed wire fences, and this in a 
region where shrikes are quite rare. 
NOVEMBERS, 1904. 
The i9oth regular meeting was held at the residence of Dr. 
H. G. Dyar, 1512 Twenty-first street N.W. Vice- President 
Banks presided, and there were present Messrs. Barber, Benton, 
Currie, Doolittle, Dyar, Gill, Hay, Heidemann, Hopkins, Mor- 
ris, Patten, Piper, Ulke, and Webb, members, and Messrs. 
Charles B. Dyar and H. J. Nichols, visitors. 
Mr. Barber exhibited c? and 9 specimens and larval skins 
of a rare Dermestid beetle, and furnished the following abstract 
of his remarks : 
1 The preservation'of the insects caught by the grass proved to be a diffi- 
cult matter, and some of the finest examples of ears, notably one that had 
captured three specimens of Pyropkorus noctilucus, were lost, partly by the 
decay of the specimens and partly by the attacks of house ants. Those I 
brought to Washington were pinned in a box which was kindly photographed 
by Prof. A. A. Doolittle. 
