7 4 s FIFTH REPORT OF THE ENTOMOLOGICAL Commission. 
elevated «>r margined, and all the ridgei marked with blaek. The pronotnm i> de* 
preeeed below the surface of the head, bol bounded posteriorly by ;i Bharp, eleyated 
baokward directed ridge, higher than the mesosternnm. All the abdominal aegmenti 
behind the first i&g. 2a) are fnrniahed with anterior and posterior dorsal trans 
rows of minute, sharp, conical tubercles <u points, the rows nearly equidistant, those 
of the movable segments Longer than the others, and with the points directed hack ward. 
The anterior row is a little more extended than the other, and is formed on most of 
gments of larger and more distant points ; in advance of it. at the line to which 
the posterior edge of the preceding segment reaches, is a shorter, delicate, fine-edged 
ridge, and a similar but blunter ridge continues the posterior row of t nbercles around 
the body. The very tip of the abdomen fig. 3d . which is truncated and blunt, hears 
a Blight coronet of points similar to those of the transverse rows. Length, 6 n,m ; 
breadth, 1 .->:»»•'». 
The moth appears to he most nearly allied to the European species R. duphuta 
Hiihn. and R. tylvestrana Curtis. From specimens of the former, which Protessor 
Zeller was kind enough to send me from Germany, it differs by its much smaller size, 
and the much greater irregularity of its markings, these being almost always clus- 
tered into four or live narrow, equidistant, transverse helts in R. dupluna: a teudeucy 
to such a transverse disposition of the markings exists also in B. frustrana, as indi- 
cated above, but mostly confined to two comparatively broad belts. From R. sylves- 
tratia, as far as I can judge by descriptions, and by a pair of English specimens sent 
me for comparison by Professor Fernald, it differs by its slightly lesser size, the color 
of the head and palpi, the differeut disposition of the markings of the wing, and 
their more brilliant and more highly variegated tints; in R. sylvestrana the stripes 
are numerous, very slender, and tend toward confluence on the basal half of the 
wing, giving it a somewhat hoary appearance, in which respect it resembles R. 
dmplana rather than R. frustrana. The pupa of B. frustrana also agrees with that of 
B. duphina, and is distinguished from that of other Retinia (that of R. sylvestrana is 
not known) in the rostrate prolongation of the anterior extremity of the body (see 
figs. 2, 3) ; the close affinity of R. frustrana to the two above-mentioned species will 
therefore be readily granted. 
Although I have not been able to follow the history of this insect completely, it is 
probably double-brooded, and differs therein from the European species, which it 
most resembles. R. duplana flies in Germany once a year only, appearing by the end 
of March or the beginning of April, and living some time into May ; the larva is full 
grown by the end of June or the beginning of July, when it changes to pupa, and in 
this condition continues eight months in the year. R. sylveBtrana is said to appear 
on the wing in Euglaud in June and Jnly, and has a similar history to the preced- 
ing, excepting in its later changes, B. frustrana appears in Nantucket between 
these two periods, or toward the end of April,* and flies at least during May : prob- 
ably most of the brood has emerged by the end of the first week in May. Eggs were 
seen in one instance May 15. and a nearly grown larva on June 18. Caterpillars may 
be found fully grown, together with an occasional chrysalid, in the middle of July: 
a little later chrysalids only can be found; and again, several years ago, I found 
larva' in great abundance, with an occasional chrysalid, about the middle of Septem- 
ber. Soon after that all change to chrysalids, for, in a subsequent year. Mr. S. Hen- 
shaw, who visited the island September IT to li>. and examined the trees carefully, 
found not more than one-sixth in the larval state, the rest in chrysalis. In all proba- 
* The earliest specimens obtained one year from chrysalids only a week or two in 
confinement in a warm room appeared on April 25 ; the earliest of those kept the 
same year in a cellar appeared May S. A single living moth, and another just dying, 
were discovered among the twigs confined in a box as late as June 23; how long 
they had been out of chrysalis there were no means of judging, but possibly several 
weeks. 
