74 
FIFTH KEPOKT OF THE ENTOMOLOGICAL COMMISSION. 
base is a short, broad, sharp-pointed spine, from the tip of which, forward, the sides 
are straight. The long, thread-like antenna- are dull yellow, with a slight duskiness 
at tin- end of each joint. The legs are blackish, with the bases of the thighs, and 
frequently of the shauks also, pale dull yellow, the hind thighs being less thickened 
towards their tips thau the four forward ones | Fitch.) 
13. Thk THUNDERBOLT BEETLE. 
Arhopaht8 fulminant (Fabr.). 
Order Coleoptera; Family Cekambycid^. 
Excavating a burrow in the soft sap-wood, about three inches long and 0.20 iuch 
in diameter, a worm like the apple-tree borer, which changes to a long-horned beetle. 
This beetle is said by Fitch to infest the oak, excavating a burrow in 
the soft sap-wood about three inches long and 0.20 inch in diameter, 
this burrow having the shape of a much bent bow or a letter U. It 
changes to a pupa in the same cell, the beetle appearing in July. We 
have also found that it bores in the chestnut, and for a description and 
figure of the beetle would refer the reader to the account of insects in- 
festing the chestnut. 
14. The white-oak piiymatodes. 
Phymatodes variabilis (Lien.). 
Order Coleoptera ; Family Cerambycid^e. 
Boring the trunk and branches of the white oak, a narrow longicorn larva, chang- 
ing to a reddish-yellow thick-bodied longicorn beetle, more or less marked with blue. 
Several specimens of this beetle were taken by Mr. Alfred Poor from 
a white-oak stick, Juue 20. It was collected on a pile of oak cord wood, 
May 30, by Mr. Oalder; and I have a specimen of it from Salt Lake 
City, Utah, identified by Dr. Horn. It is undoubtedly closely similar 
in its habits and in the form of the larva to the grape Phymatodes fig- 
ured in our first report on the injurious insects of Massachusetts, and is 
one of our more common species of the genus. 
Beetle.— It is closely allied to P. amevnus, but is larger 
and less coarsely punctured, while the antennae are 
more reddish; the scutellum is concolorous with the 
wing-covers. The body, legs (except the femora, which 
are blackish in the middle), and antennae are reddish, 
the tips of the joints of the latter dark, and on the 
back of the prothorax are two black spots, ofteu con- 
fluent. The head is black. The wing-covers are Prus- 
sian blue, smooth, fiuely punctured, with rather thick, 
fine, black hairs, bent downwards. Specimens recently 
changed from the pupa state are brown, and the species 
is exposed to considerable variation, as its name indi- 
cates. The male is just half an inch long, the female 
.60 inch. 
The foregoiug description is taken from our second report on the in- 
jurious insects of Massachusetts. The pupa of this beetle was also 
Fig. 23.— Phrmatodes variabilis — 
Smith, del. 
