1881.] Entomology. 749 
of 1876, and a sidewalk was laid immediately above them. This 
walk has not been moved since that time, until the eggs were 
found. The earth which covered the eggs was principally clay, 
old mortar and bits of stone, though there was some black earth 
immediately surrounding the eggs.” 
The eggs were found, it seems, while men were cleaning away 
an accumulation of spalls, mortar and clay, and the sidewalk above 
referred to, in the rear of the laboratory. We learn that the eggs 
were about ten inches below the sidewalk and certainly not deep 
enough to be entirely out of the influence of the changing tem- 
perature of the year. Appearing fresh when dug up they were 
placed by Mr. Graham under favorable conditions for hatching, 
and in due time a lively swarm of locusts issued. 
We have, in our own experience, in rearing insects, often known 
of retarded development both in larvae and pupe to the second 
and even the third year; but in this instance we have a well 
authenticated case of eggs remaining unhatched for nearly 4% 
years. The fact that the species is Ca/optenus spretus (which, to 
our knowledge, so abounded around Manhattan in the fall of 1876 
that the ground all around the college was absolutely full of eggs) 
is confirmatory of the statement of Mr. Graham, because the 
species did not occur there nor in that part of the country last 
fall, nor in fact during any year since 1877. The eggs above re- 
ferred to must be a retarded remnant of those which were so 
thickly laid there in the fall of 1876 and which gave birth to the 
destructive multitudes of young locusts the ensuing spring. 
PROMOTION OF SILK-CULTURE IN CaLirorniA.—Mrs. Theodore 
H. Kittell, corresponding secretary of the California Silk-culture 
Association, San Francisco, Cal., writes: “ We have, through our 
efforts, succeeded in convincing our people of the practicability of 
home silk culture, and by lectures, distribution. of pamphlets, 
mulberry seeds, slips and silkworm eggs we have now so animated 
the public that complete success seems certain, if we shall be able 
to start a filature for the reeling of the silk produced. Our 
society takes the liberty of asking you as one of the most 
urgent workers for silk-culture in America to give us your advice 
as to a filature, and the best and cheapest mode of preparing the 
t for the market.” oaak i | 
We would refer for our opinions on the subjects mentioned to 
our “ Manual of Instructions for the production of Silk,” which 
can be obtained, upon application, of the Commissioner of Agri- 
culture, 
Locusr Fricuts in Dakora.—Mr. Geo. W. Hart of Columbia, 
Brown Co., Dakota, reports that a flight of locusts ( Caloptenus 
Spretus) passed over that place from 11.30 A. M. to 3.30 P. M. on 
the 7th of July, coming from S.S.E., the wind being strong and 
the weather dry. On July 16th, another correspondent, Mr. F. 
¢ 
