Magrcw 1, 1912] 
green, another on pink and a third on brown. 
Why I can’t get enough colors to go areund.’’ 
An energetic collector with time and money at 
his disposal can make some sort of type out of 
seventy-five per cent. of his species. These vari- 
ous types may have some value, but they can not 
always be depended upon. A great number of 
colors used indiscriminately is very confusing, for 
there are equally important features that might be 
designated by color, aside from manufactured 
types. Colors could be used to advantage to indi- 
cate abnormalities, especially to-day when the ex- 
perimental biologist is after data as to the number 
and kinds of abnormalities that occur in specimens 
in nature. ‘Such specimens are completely over- 
looked unless they are marked in some way. Not 
more than two colors should be used for types: red 
for the primary, and green for supplementary 
types. Then another color, yellow, for instance, 
could be used for abnormalities. 
HERBERT OsporN: A Problem in the Flight of 
Insects. 
Insect flight has been explained continuously by 
the movements of the wings vertically, the rigid 
anterior border with flexible hinder portion of the 
wing serving to so relate itself to the atmosphere 
as to furnish a forward movement. While this 
explains readily the forward progression, it does 
not in itself explain the hovering or the backward 
flight of many insects which is a matter of com- 
mon observation. Numerous instances cited illus- 
trate this feature. The explanation suggested for 
this movement is that the wings are rotated for- 
ward until the flexible under-portion of the wing 
reacts upon the atmosphere in such manner as to 
maintain the insect in a stationary attitude or 
even to propel it in a backward direction. Such 
rotation may be seen to be amply provided for in 
the structure of wings and the close observation of 
insects in hovering indicates the forward rotation. 
BE. P. Fevt: The Biology of Miastor and Oli- 
garces. 
The widely distributed Miastor larve reproduce 
by pedogenesis in the moist, decaying bark of 
various trees during fall and spring, midges ap- 
pearing from June till August.. A larval genera- 
tion oceupies three to three and a half weeks. 
Oligarces is less common than Miastor. Both are 
subject, to attack by a number of natural enemies. 
Lronarp HasEMAN: Entomological Work in Mis- 
souri. 
Since the early masterly work’ of Dr. ©. V. Riley 
the entomological needs of Missouri have not been 
SCIENCE 
353 
properly served. Every line of entomological work 
is open for study. This department is investi- 
gating the more urgent insect problems of Mis- 
souri, though it is much handicapped by lack of 
assistance. The work connected with the instruc- 
tion, station, nursery inspection and duties of 
state entomologist is more than the present staff 
can properly handle. 
W. L. W. Fieto: Hybrid Butterflies of the Genus 
Basilarchia. 
Since the Boston meeting two years ago, con- 
siderable progress has been made in the experi- 
ments with the supposedly hybrid Basilarchias, B. 
proserpina Edw. and B. arthechippus Scud. Their 
hybrid nature has now been proved by breeding 
experiments. ‘The data obtained also support the 
conclusions drawn from earlier experiments, to the 
effect that in proserpina the black of astyanaxz is 
incompletely but uniformly dominant over the 
white-banded condition of arthemis. 
O. A. JOHANNSEN: Cocoon Making of Bucculatria 
canadensisella. Read by title. 
J. G. NEEpHAM: Some Adaptive Features of 
Myrmeleonid Venation. Read by title. 
E. H. Srrickntanp: The Pezomachini of North 
America. Read by title. 
P. P. CatvERT: Seasonal Collecting in Costa Rica. 
Read by title. 
Z. P. Mercatr: Homologies of the Wing Veins of 
Homoptera Auchenorhynchi. Read by title. 
The following annual publie address was given 
at the Cosmos Club, Wednesday evening, Decem- 
ber 27: 
J. H. Comstock: The Evolution of the Webs of 
Spiders. Illustrated. 
It is probable that the production of silk by 
spiders was not primarily evolved for the making 
of webs for capturing prey. The representatives 
of many families do not spin webs; and there is 
no reason to believe that these non-web-making 
families have descended from web-making forms. 
All spiders use silk in caring for their eggs; and 
it is probable that this was the primary use of silk 
in this group of animals. 
Spiders having acquired silk for the protection 
of their eggs have utilized it for other purposes, 
of which the making of webs for capturing prey is 
but one, and probably not the next one in the 
sequence of the different uses of this substance. 
The acquiring of the habit of spinning a drag-line, 
the thread which most spiders spin wherever they 
go, doubtless preceded the making of webs. A 
spider spinning a dtag-line would make a web if 
