THE CANADIAN ENTOMOLOGIST. — 49 
adult larvæ of allied genera. Indeed, this statement is perhaps too feebly 
formulated, so important are many of the distinctions which have been 
traced. These differences, it should be noted, 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 character, definitely dis- 
posed, display, in mature life, irregularly distributed, scarcely perceptible 
warts, emitting simple and nearly microscopic hairs ; while others, which 
in their earliest stage bore regular series of simple hairs, seated on little 
warts, become possessed, at maturity, of compound spines, surmounting 
‘mammulz, also definitely arranged, but occupying a very different position 
to the hairs of early life. So, too, we find some caterpillars which bear a 
tuberculated, irregular head in infancy, and a smooth and equal one at 
maturity ; or the reverse, where the head is simple at birth, and heavily 
spined or cornute when full grown; others, again, remain almost ur- 
changed through life. This latter condition of uniformity never applies to 
the appendages of the body, whether we consider their character alone or 
their disposition. Nor—the only other possible condition—do we ever 
find larvæ bearing only irregularly distributed, simple, minute hairs in 
infancy, and regularly arranged special appendages at maturity. Indeed, 
it is doubtful whether such a phenomenon exists in Nature ; since in the 
numerous and varied groups that have been examined, special dermal 
appendages have been found to be an invariable characteristic of embry- 
onic larvæ. / 
August, 1871. 
NOTES ON THE LARVA OF 
ACRONYCTA OCCIDENTALIS, Grote. 
BY W. SAUNDERS, LONDON, ONT. 
THIs insect in the imago state closely resembles A ps7, of Europe, and 
has been, and we believe still is, doubtfully regarded as identical by 
several eminent European entomologists., We think, however, that a 
comparison of the larval forms of the two insects will help to dispel any 
doubts which may be entertained regarding the dissimilarity of the spe- 
cies. The following description of the larva of occidentalis has already 
appeared in part, in the Annual Report of the Entomological ‘Society of 
Ontario to the Commissioner of Agriculture for 1870, where it is given, 
