December, ’23] 
SCIENTIFIC NOTES 
553 
Unusual Damage to the Floors of a House by a Species of Pemphredinid Wasp, 
Stigmus fulvicornis Rohwer. During the latter part of August 1923 the writer 
was requested to visit the home of Mr. Ed. Williams in Starkville, Miss, and investi¬ 
gate the damage to his floors caused by what he thought to be ants. After reaching 
Mr. Williams’ home the writer was very much surprised to find a portion of the 
floor of his porch bearing numerous holes about the diameter of the head of an 
ordinary pin or slightly smaller. By the side of a number of these holes were small 
piles of sawdust. Flying in the air above these holes and crawling on the floor here 
and there were numerous small wasps which on superficial examination might have 
been taken to be parasites of whatever insect was damaging the floors. The holes in 
the floor bore a striking resemblance to those of Ipid beetles, in fact the writer would, 
upon a hasty examination, have concluded that a species of Ipid was the depredator 
and that the wasps were parasites on them. A very careful examination of several 
nests proved that the wasps were the cause of the damage and that they were using 
the .floor as a place in which to construct their nests. A number of the insects were 
secured but they were so immature that no effort was made to have them determined. 
With the literature available the writer was able to place the wasp in the genus 
Stigmus. Specimens were forwarded to Mr. S. A. Rohwer, of The United States 
National Museum, with a request for a specific determination. Mr. Rohwer wrote 
that the species was nearest S. conestogorum Rohwer, but differed from this species 
in a number of ways, enough to warrant him in calling it a new species, to which he 
gave the name fulvicornis because of its yellowish or ferruginous colored antennae. 
Air. Rohwer took issue with the writer in regard to the wasp’s ability to construct 
nests in the floor. He was of the opinion that the wasps were using the holes made 
by Ipid beetles or else nail holes for their nests. There is no doubt about the wasps 
constructing holes in the floor as Air. Williams observed them carrying sawdust-like 
frass out of their holes. The writer also examined enough of the nests to be con¬ 
vinced that the wasps were solely responsible for the nests and not the wood-boring 
beetles, as one would ordinarily think. 
A review of the literature dealing with the habits of the wasps of the genus Stigmus 
contains no reference to any species of the genus ever having attacked furniture or 
floors; normally the wasps breed in the stems of plants or twigs of trees but there is 
a reference to one species having been bred from a gall. It is left for one to speculate 
as to why this species should attack floors when there were plenty of trees and plants 
nearby in which it might have constructed its nests. Will this species continue to 
be a household pest or was this simply a variation in the habit of the wasp? 
On September 10th, a further visit was made to the home of Air. Williams where 
the writer’s attention was called to the holes made in the floor of the dining room 
and hall. The floor was hard and well preserved, and not soft and punky like that 
of the piazza. Both floors were of pine but that of the piazza had been subject to 
weathering, while that of the interior of the house was almost as well preserved as 
it was when the house was built. After seeing the nests in this type of wood one 
was more than ever convinced of the wasp’s ability to construct nests in other kinds 
of wood besides soft and decaying lumber. As a rule the nests in the interior of the 
house were constructed in the soft wood between the hard grain layers but this 
was not invariable, for a number of nests were observed which penetrated even the 
hard grain layers. On the porch a count of the nests occuiring in one plank was 
made and it was found that fifty nests occupied this plank, which w r as about three 
