SEPTEMBER 10, 1897. ] 
Dr. H. Loew, in his well known paper, 
“Ueber die Diptern-fauna des Bernsteins,’ 
has shown that several of the species of the 
genera Oscinis and Chlorops have gained a 
wide distribution through commerce, and 
this probably happened through their oc- 
currence in hay or straw used as packing, 
since they live in the stems of grains and 
grasses. Dr. Loew, by the way, considered 
the Diptera, by virtue of the simple condi- 
tions required for their existence, to be 
peculiarly susceptible to commercial and 
accidental distribution, and was inclined to 
believe that the majority of the many 
species common to Europe and North 
America have been imported into the latter 
country. He understood, however, the ex- 
istence of a circumpolar fauna and wrote 
wisely and learnedly about the common 
ancestry of what he called analogous 
species. Whatever may be the cause, the 
Diptera seem fitted in the individual to 
withstand widely differing environmental 
conditions. The group, as a whole, has ap- 
parently little faunistic value either along 
broad lines or in a more restricted way. 
There are comparatively fewer character- 
istic genera in the main faunal regions of the 
world than in other groups of animals, and 
in our own country there are comparatively 
few species of restricted distribution. Very 
many individual species range through the 
Lower aud Upper Austral, through the 
Transition and into the Boreal regions. 
Aside from the Diptera, grains and 
grasses all over the world are subject to the 
attacks of a host of insects of all kinds, 
many of which hibernate on or within the 
stems, so that the proposed legal provisions 
of the English colonies mentioned are by 
no means unwise. The substitution of the 
wood material known as ‘excelsior,’ the 
use of which is becoming so common in this 
country, or of some other packing material, 
will shortly do away with a large share of 
this danger. 
SCIENCE. 
393 
There are, of course, other less important 
methods by which insects may be trans- 
ported, such as in earth or damp moss about 
the roots of plants and in sand used for 
ballast. These methods, however, are not 
very important as a rule, although it is 
stated that the destructive chigoe (Sar- 
copsylla penetrans) was carried in ballast in 
1872, on a vessel from Rio Janeiro to the 
coast of Guinea, where it has established it- 
self most perfectly, having been found 200 
miles inland by Stanley.* 
There remains one more source of acci- 
dental introductions and it is one which 
has been reasonably prolific as regards in- 
sects on several occasions. I refer to inter- 
national expositions, which are now becom- 
ing of almost annual occurrence. At the 
Centennial Exposition at Philadelphia, in 
1876, the insects occurring in the exhibits, 
especially of foreign grains, received some 
study by Dr. Riley, who published a short 
note in the Proceedings of the St. Louis 
Academy of Science for October 2, 1876. 
A special committee of the Philadelphia 
Academy, consisting of Drs. Horn, Leidy 
and Le Conte also prepared and published 
a report at this time, but none but well 
known and cosmopolitan forms were found. 
I am not familiar with the results of any 
studies of a similar nature made at the 
Paris Exposition Universelle of 1889, but 
have seen the title of a paper by M. Decaux 
which reads ‘Etudes sur les insectes 
nuisibles receuillis 4 VEHxposition Uni- 
verselle,’ Paris, 1890, which, however, I 
have not been able to consult. 
In 1893, however, careful observations 
were made at the World’s Fair at Chicago 
by Mr. F. H. Chittenden, the results of 
which were published by Dr. Riley in Vol- 
ume VI. of Insect Life. Insects to the 
number of 101 species were found in grain 
and other stored vegetable products. Seven 
species were found affecting animal products 
* “Die Umschau,’ July 17, 1897, p. 523. 
