248 ENTOMOLOGICAL SOCIETY 
SEPTEMBER 5, 1889. 
Eight persons present. President Schwarz in the chair. 
Dr. Marx added two genera of spiders, Synemosyna and Syna- 
geles, to the list of myrmecophilous insects presented by Mr. 
Schwarz at the 'previous meeting. 
Mr. Ulke mentioned that he had found a specimen of Micro- 
rhopala melsheimeri in an ants' nest at Pen Mar, Pa. This spe- 
cies might prove to be a true myrmecophilid. 
Mr. Schwarz thought that it could only be a messmate of the 
ants in the larva state, if it was not a mere accidental find. 
Mr. Ulke, in connection with Mr. Edwards' paper on the 
noises of Lepidoptera, mentioned that he had this season repeat- 
edly heard the stridulating noise produced by Harpalus caligi- 
nosus in specimens attracted by electric lights. The noise ceased 
as soon as the specimens were caught. 
Mr. Schwarz corroborated Mr. Smith's statement made at the 
last meeting regarding the appearance of Cicada septcndecim in 
the northern part of the District. He had traced the species (from 
pupaB skins adhering to trees) from Glenwood Cemetery around 
Soldiers' Home and across yth-street Road, but did not see them 
in the woods bordering Rock Creek. The first Cicada pruinosa 
was heard this year on July 5. 
Mr. Schwarz read the following paper : 
SUDDEN SPREAD OF A NEW ENEMY TO CLOVER. 
By E. A. SCHWARZ. 
The sudden appearance of any species of insects in great number of 
specimens is always an interesting phenomenon. If such species was pre- 
viously known to occur in the same locality, though as a rarity, we ex- 
plain this appearance in numbers from the fact that the conditions, cli- 
matic or otherwise, have been exceptionally favorable for its increase. 
But if a species suddenly appears abundantly in a locality in which it for- 
merly did not occur in other words, if we have an invasion or a sudden 
migration of a species the reasons for such movements remain in most 
cases obscure. It is an example of this sort which has come under my 
observation within the spring and summer of this year, and which I would 
like to place on record. The insect in question is a Curculionid, Sitones 
hispidulus, a species introduced from Europe, but whose occurrence in 
North America has been known for quite a number of years. 
The genus Sitones contains a tolerably large number of palearctic species, 
