170 ZOOLOGY. 
than are to be found in the adult larve of allied genera. By the 
term “embryonic” he designates those caterpillars which have 
not changed their condition since leaving the egg, a stage in whieh 
they generally continue but one or two days. Some of the changes 
alluded to are more or less gradual in their appearance, but they 
generally occur at the first moulting of the caterpillar. 
He incidentally remarks that in studying caterpillars “ the shape 
and sculpturing of the head, the form of certain segments, and 
especially the precise number, location and disposition of the 
spines, thorns, and hair-emitting warts of the body will be found 
to furnish abundant means of distinguishing the most closely 
lied and minutely subdivided genera.” f 
The differences he proceeds to describe ‘are not always in the 
same direction ; for we have seen that caterpillars which in infancy 
are clothed with appendages of a unique and conspicuous chan 
ter, definitely disposed, display in mature life irregularly distri 
buted, scarcely perceptible warts, emitting simple and nearly mi- 
croscopic hairs; while others, which in their earliest stage bore 
regular series of simple hairs seated on little warts, become r 
sessed at maturity of compound spines, surmounting mammulæe, 
so definitely arranged, but occupying a very different position to : 
the hairs of early life. So, too, we find some caterpillars wh 
a tuberculated irregular head in infancy, and a smooth and eq 
one at maturity ; or the reverse, when the head is simple 
and heavily spined or cornute when full grown ; others, 
main almost unchanged through life. This latter con 
again, Te 
dition of 
whether 
we consider their characters alone, or their disposition. 
the only other possible condition—do we ever find larv 
ich beat 
E 
at birth, a 
only irregularly distributed, simple, minute hairs in infancy, 8 
„itis 
regularly arranged special appendages at maturity Taa m 
doubtful whether such a phenomenon exists in nature ; SHS 
istic of embryonic larvæ.” 
Proracatios or Satmon.—During the past season 
attempt to obtain eggs of the sea-going Salmo sa 
limits of the United States was made at Orland on : 
River ; and as this was also the first authenticated expe"! 
