During the spring of the past year I was fortunate enough to procure eggs of the following species of Scopelosoma, and succeeded in rearing a sufficient number of each to ensure an accurate observation of their larval differences. The matter is of some interest, as it settles beyond question the specific difference between the two species known in collections as S. Walkeri and S. vinulenta, which have been enumerated as varieties of the mythical sidus in recent lists. That one of these species is really sidus I think there can be little doubt; but which should be referred to it is somewhat uncertain.