
ar, 
1891.] Entomology. i 673 
winter. Soon after hatching a brood the lobster may moult, but eggs 
are not laid again until at least another year. 
When the young lobster hatches from the egg it moults, and in arti- 
ficially hatched lobsters large numbers die on account of inability to 
pass this moult. After six or seven days the second moult occurs. 
Young lobsters swim at the surface six to eight weeks, and then dis- 
appear entirely from the surface. 
The second paper deals with the growth of the reproductive organs, 
and the stages as far as the nauplius-like condition. The greatest dif- 
ferences appear in the segmenting eggs. -The egg nucleus, with its 
surrounding protoplasm divides near the center of the egg, and its 
products wander to the surface, and the periphery breaks up into 
irregular cells. Until about 40 hours after fertilization the peripheral 
yolk is entirely segmented. About 30 segments are present. In all 
the segmentation stage occupies three days. By the end of the fourth 
day the invagination stage is reached. This is followed by the keel 
stage, which lasts about four days. At the beginning of the tenth day 
the nauplius appendages begin to bud, first the first pair of 
antennæ and mandibles together, and a little later the second pair of 
antennæ. 
ENTOMOLOGY. 
The “ Arrow Weed” and Mexican “Jumping Bean’ 
Insect.—It has long been known that the Indians in Mexico make a 
powerful poison from some native plant, which poison, in a milder 
form, is also used as a cathartic. It has also long been known that 
seeds possessing the curious power of jumping are produced upon the 
same plant in Mexico, and are sent to other parts of the world, form- 
ing quite an article of commerce. The exact nature of this plant, 
however, has hitherto remained a mystery. At a recent meeting of 
the Washington Entomological Society, Professor C. V. Riley read an 
interesting paper on the determination of the plant upon which these 
‘jumping seeds” are produced. In the Transactions of the St. Louis 
Academy of Sciences for 1875 is an account of Carpocapsa saltitans 
Westwood, the insect which causes the saltation of the ‘‘ beans,’’ he 
had called attention to the fact that the particular euphorbiaceous 
plant upon which these seeds are produced was not determined. 
Westwood, in his original description of Carpocapsa saltitans, states 
that the plant is known to the Mexicans as Calliguaja, and in a recent 
