Bibliography— Editorial. a7 
interesting details about many species of injurious insects found 
in Colorado in 1888. Several appear to have been very recently 
introduced into Colorado, and this suggests the enquiry whether 
the Exper. Station itself may not be unwittingly bringing insect 
pests on imported shrubs and herbs, which would never other- 
wise cross the arid plains to the east of Colorado. Pieris rapz is 
said to have established itself in Colorado, although Prof. Cassi- 
dy’s description does not read like rape; sesia tipuliformis is an- 
other presumed introduction. Among insecticides; powdered 
‘veratrum albrem is recommended. We wonder whether the V. 
californicum (called albrem by Watson), which is common in 
parts of Colorado. would suffice in its stead? The report is un- 
fortunately marred by several misprints in the spelling of scien- 
tific names, but altogether, is both interesting and valuable. 
| LD). wa OG, 
T.D. A. CoCKERELL. Preliminary remarks on the Mollus- 
can Fauna of Colorado. ‘Journal of Conchology,’ Vol. VI, 
1889, pp. 60-64. A preliminary survey of the Mollusca of Colo- 
rado, several species are added to the State list, and a new spe- 
cies of Physa is described. 
ForcE AND ENERGY. A Theory of Dynamics; by Grant 
Allen. Humboldt Publishing Company, 24 East 4thstreet, New 
York. The author defines Force and Energy as the two mani- 
festations of power, tending to initiate aggregative motion, find- 
ing its expression in gravitation, adhesion, chemical affinity, and 
imperfectly comprehended electrical affinity, and showing its vi+ 
tality in the separative powers classified as molar, molecular, 
chemical and electrical modes or manifestations of motion. . 
HDITORTAL: 
The lichens collected by the editor have been placed in the 
hands of a specialist, who will carefully identify them and pub- 
lish the results of his studies in this magazine. The duplicate 
sets of these lichens will be offered for sale or in exchange and 
distributed whenever a fascicle may be prepared. Those desir- 
ing the more complete sets should apply at once, as many, likely 
the new and rarest species, were sparingly collected. We should 
be pleased to have collections of lichens from’ any of our West 
American correspondents to include in our own series and for 
distribution. We enjoyed recently a pleasant visit from Dr. C. 
C. Parry, whois again on the Coast, persistently following up his 
acquaintance with some of our equally modest and retiring wild 
flowers. A new species of eriogonum, of which our readers 
will learn more soon, rewarded his search through our herba- 
rium. Our Colorado notes are selected from the reports of the 
Colorado Biological Association, prepared by the Secretary and 
