1923] Occurence of Muscina pascuorum in North America 
5 
Europe and North America. It is found from August to early 
November, and some of the members of the Club say that it was 
quite common this year. Charles Mcllvaine (One thousand 
American Fungi, p.7. 1900) considers it only a form of A. phal- 
loides. Miss Conant also reported a number of other species of 
Amanita, including A. phalloides, as being common, and as 
early as July, If Muscina pascuorum is strictly fungicolous, 
the abundance of these fungi might account for the rapid in- 
crease of this fly during the autumn. 
The wide distribution that this fly has attained in this 
country before being discovered, makes it difficult to ascertain 
where the species was actually introduced. The prezence of the 
fly in Connecticut and New Jersey at least two months before 
being observed in the vicinity of Boston, is an indication that 
it was probably introduced somewhere near New York City, 
sometime prior to the present year (1922). This theory is 
strengthened by the usual or apparently natural line of dispersal 
of species in a northerly or northeasterly direction, as followed 
by most of the introduced species; e. g., elm beetle, asparagus 
beetles, leopard moth, gipsy moth, etc. 
Its present distribution would indicate a still wider dispersal 
if all records were available. Its habit of entering houses would 
also induce it to enter railroad cars and thus be rapidly and 
widely transported over the country, a factor that probably 
partly accounts for its sudden and wide-spread appearance. It 
promises to be as great a nuisance to housekeepers as the cluster 
fly {Pollenia rudis) which often enters houses in great numbers 
in the autumn. The last living specimen of Muscina pascuorum 
was received from Dr. Lewis, Waban, Mass., December 14. It 
will probably continue to appear in lesser numbers during the 
warm days throughout the winter and spring. A study of its 
habits and dispersal during the coming year will prove very 
interesting. 
