24 
BULLETIN OF THE BUREAU OF FISHERIES. 
from the underlying tissues preparatory to transformation. The pupa whose 
chamber was opened just as it was about to transform was dark gray-brown in 
color, but this color was in the skin, for the beetle that emerged was snow white. 
The average total length of the pupae was 35 mm., the greatest width at the 
third thoracic segment 15 mm., the thickness of the combined head and thorax 
12 mm.; the posterior cerci were 4.25 mm. long and the anterior spines were 5.5 
mm. long. 
The head of the pupa is curved downward onto the chest, its anterior margin 
just reaching the bases of the second legs. This folding back of the head leaves the 
prothorax as the most anterior portion of the pupa. The eyes are partially con- 
cealed beneath the anterior corners of the prothorax, and just inside the center of 
each eye is a small spine. Elsewhere the head is smooth and its length is about 
equal to the width through the eyes. At the posterior margin of the head on the 
dorsal surface there is a small, transversely elliptical spot on either side of, and 
close to, the median line. The surfaces of these spots are depressed a little, espe- 
cially on their posterior margins, and they turn much darker in color than the sur- 
rounding tissue. They entirely disappear in the adult beetle. 
The antennae, the mouth parts and legs, and the long posterior spine of the 
metasternum are encased in separate sheaths, the antennae curved around beneath 
the eyes as in the imago and the maxillary palps extending backward ventral to 
all the other parts as far as the first abdominal segment. The articulations of the 
antennae, the palpi, and the tarsi of the legs are distinctly visible in older pupae. 
In the sheaths inclosing the legs there are separate branches for each of the large 
spines at the distal ends of the tibiae. 
Attached to .the pupa case at each anterior corner of the pronotum are three 
curved styli 5.5 mm. long. They are reenforced at their bases by rootlike proc- 
esses formed of folds of the pupa case, making them very strong. They taper 
gradually from the base to the tip, and the distal third is transversely ridged and 
terminates in a short and slender bristle (fig. 17). Around the posterior and 
lateral margins of the pronotum is a row of 12 short styli, similarly ridged for their 
entire length and each tipped with a bristle. On the dorsal surface of the second 
thorax segment is a pair somewhat larger, one on either side of the scutellum, and 
another pair on the third thorax segment. The dorsal surface of each abdominal 
segment except the last bears a transverse row of four similar styli. The two cen- 
tral ones are about the size of those on the thorax but the lateral ones are nearly 
as large as those at the anterior corners of the pronotum. The last segment of the 
abdomen bears a single pair smaller than any of the others and directed backward 
from its posterior margin just above the cerci. On the ventral surface of each 
abdominal segment from two to six, inclusive, close to either lateral margin is a 
single tiny stylus. 
All these styli are ribbed for their entire length and tipped with bristles. They 
are also a part of the pupa case and are left behind with the case in the pupal chamber 
when the beetle emerges. Their use is thus explained by Lyonet (1832), who reared 
the larvae of the European species piceus: 
In the damp earth which the pupa requires the hooks fullfil a purpose of great importance. The 
skin of the pupa is very delicate. Lying on damp earth it could hardly escape injury, and the weight 
