290 
BULLETIN OF THE BUREAU OF FISHERIES. 
The eyes are large, light reddish-brown in color, and widely separated; the antenna extend 
diagonally outward and backward to the edge of the elytra; the maxillary palps are short and reach just 
beyond the first legs. The femora of the first and second legs are at an angle of 45° with the body axis, 
the tibia and tarsi are nearly in a straight line and overlap at the center of the body; the femora of the 
third legs are at an angle of 90° with the body axis, or drawn a little farther forward than that; the tibia 
and tarsi are in a straight line and overlap as in the other legs, their tips reaching the middle of the 
penultimate abdominal segment (fig. 48). 
The following table gives the time spent in the pupal chamber before pupating and the length of the 
pupal stage in 10 specimens: 
Entered chamber. 
Pupated. 
Emerged. 
Entered chamber. 
Pupated. 
Emerged. 
1919. 
July 12 
July 13 
July 18. 
July 23. 
July 24. 
1920. 
Aug. 6 
Aug. 8 
Aug. 14. 
Aug. 15. 
July 1 5 
July 17 
Aug. 9 
July 17 
July 19 
1920. 
1921. 
July 14. . . 
July 17. . 
July 23. 
July 26. 
Do. 
July 16 
July 17 
July 23. 
July 26. 
July 18 
July 20 
July 20 
July 22 
July 19 
July 21 
Habits of the adult . — The hind legs of this species are very heavily fringed with swimming seta, and 
hence it can swim rapidly and with much agility. It is also the best jumper of all the beetles studied 
with the exception of Thermonedes omaticollis, and the jumping is accomplished by the hind legs. This 
beetle is found in every fishpond except 6D, and could probably be found there if the search were made 
persistent enough. Its small size makes it harmless to the fish, and in its turn it serves as food for 
fish, frogs, and some of the other beetles. 
Description of the adult . — General outline ovate, nearly elliptical, but somewhat narrowed posteriorly 
and strongly depressed. Total length 6 mm., greatest width 3.50 mm. Thorax very short, more than 
three times as wide as long and without widened margins; scutellum practically invisible; elytra widest 
near the center, obliquely truncated anteriorly and posteriorly, with one or two rows of minute punctures. 
Tarsi of the first two pairs of legs in the male enlarged and armed with spongy, prehensile hairs, two rows 
on the basal joint and one row on the second and third joints. The coxae of the third legs are expanded 
into broad processes, concealing the coxal cavities. The coxal plates in the male are furnished with a 
stridulating file, whose ridges begin at the inner margin near the center and extend outwards and back- 
wards. The third legs are much flattened and armed with two rows of long swimming setae ; the spines on 
the inner margin of the tibia near its distal end are unequal and distinctly emarginate at their tips. The 
antennae are cylindrical, filiform, and 11-jointed; the mandibles have a wide terminal margin, which 
is only slightly reentrant, with an acute ventral tooth and a blunt dorsal one. The maxillary palps are 
four-jointed, somewhat club-shaped and rather short; the labial palps are very short and two-jointed. 
The head, thorax, and under parts are reddish-yellow, the elytra black, each with four submarginal spots 
and three basal lines of greenish-yellow. 
Laccophilus proximus Say. Figures 40, 42, 45, 47, 49. 
Laccophilus proximus (Say, 1825, pp. 101 and 514). 
Eggs . — In this species, as in the preceding one, the eggs are probably deposited singly in the stems 
of water plants. 
Habits of the larva . — This larva has the same habits and eats the same food as the maculosus larva, 
but is much less cannibalistic. Indeed, not once did it betray any such tendencies, and when the two 
species were kept together, although the maculosus larvae attacked one another and also killed and ate 
the proximus larvae, the latter never retaliated. 
Description of the larva . — This species is considerably smaller than the preceding for two reasons — 
the first three and the last abdominal segments are actually shorter, and then the larva keeps all the 
segments telescoped even when suspended from the surface film during breathing. Hence, while 
the maculosus larva averages about 8 mm. in length when fully grown, the proximus larva is only from 
6 to 6.5 mm. long. 
Proximus is also much the darker of the two, the entire upper surface being dark brown, with the 
margins of the sclerites nearly black. In the center of the dorsal surface of the head is a dark brown 
