i t 20 Bulletin N 0. 231
the trees when these were cut open. No pupae or adults were,
however, found in the burrows, and but few young grubs of V
the size generally to be taken from trees at this season of the .
year. Nor has a careful search of walnut trees* in the vicin .
ity revealed other adults. There are no hickory in the im- A
mediate vicinity. pl
For some time the author has been disposed to accept the T
t views of B. D. Walsli and Dr. Horn as to the distinctness of
the spring and fall forms known under the names Oyllcne rob- 2
iniac and C. picta, tho he formerly had doubts as to the re- l
liability of the characters used by them. The facts given above
( suggest several alternatives as possible explanations of the re-
lations of the spring form with those so common on goldenrod
and locust trees in the fall: '
(1) Either there are two distinct species, as has long been `
assumed, one living on hickory and walnut and appearing in the
spring of the year as adults, the other living on locust and ap- Q
pearing as an adult in the fall. .
(2) Or, there are two forms of one species, one form ap- `
- _ pearing in spring as adults on locust, hickory and walnut, the
other appearing only on locust in the fall.
(3) Or, there are two forms of the Locust Borer, one .
maturing in the fall, the other in the spring, the latter brood
~ diifering in no essential feature from the species appearing as Y
adults on hickory in spring. V
E At present the writer is disposed to accept the second of
these hypotheses, and to hold that a spring brood, the males
Y with stronger, longer antennae and both sexes with a tendency i
_ to grayness in the markings, appears on several different trees, .
` the locust among them, while a second form of the same species (
appears in fall only on the locust. The facts here given at Q
least reopen the question as to the distinctness of the borers, and
add a fact of some economic importance to our knowledge of .
the habits and life-histories of these insects. ,
of the early writers on the Hickory Borcr claimed that it at- Y
tacks black walnut, and l`itcl1 (Fifth Ann. Heir ii. Sl) assertcrl that this .
tree produces larger beetles with gray instead of yellow bands,