EGG AND FIRST-STAGE LARVA OF TARSOSTENUS 
UNIVITTATUS (ROSSI), A BEETLE PREDACIOUS ON 
POWDER-POST BEETLES 1 
By R. A. St. George 
Assistant Entomologist , Forest Insect Investigations , Bureau of Entomology , United 
States Department of Agriculture 
INTRODUCTION 
The family Cleridae has long been 
recognized as one of considerable 
economic importance because of the 
predacious habits of the beetles, both 
in the larval and adult stages. Cham¬ 
plain (f) 2 states that “they are among 
the principal predators of wood and 
bark boring beetles, the adults attack¬ 
ing the adults of the destructive 
species while the larvae feed upon the 
eggs and broods in the bark and wood.” 
And he continues: 
“Under natural conditions they may 
be of but normal importance but can 
be turned to considerable account in 
control measures with the additional help 
of man, who can overbalance the natural 
conditions in favor of the predators by 
properly conducting control work.” 
The beetle Tarsostenus univittatus 
(Rossi) 3 is one of the clerid species and, 
according to Champlain (1), princi¬ 
pally a predator on powder-post beetles 
such as Lyctus and Xylobiops (=Sinox- 
ylon) in dry, seasoned wood products. 4 
Of this species several living adults 
were obtained while the writer was 
supervising a series of experiments 
which were recently conducted by the 
Bureau of Entomology in cooperation 
with the Naval Aircraft Factory at the 
League' Island Navy Yard, Philadel¬ 
phia, Pa., to determine temperatures 
fatal to the powder-post beetle Lyctus 
planicollis Le Conte by steaming in¬ 
fested ash and oak lumber in a kiln (5). 
Additional infested ash lumber was 
sent to the Forest Insect Laboratory, 
East Falls Church, Va., and several 
adult beetles were secured from this 
material to be placed in cages for rearing. 
TRANSFORMATION TO ADULTS 
AND MATING 
Most of the beetles probably pass 
the winter in the larval stage, although 
a few may pupate before early spring, 
especially if they are in wood which is 
kept in a heated building. In De¬ 
cember, 1923, samples of infested wood 
were placed in a heated building and 
were kept at a temperature of 70° F., 
or slightly higher. When examined five 
weeks later, most of the beetles were in 
the larval stage, but two pupae and three 
maturing adults were found. This is 
in accordance with the statement of 
Champlain ( 1 ) that “clerids over¬ 
winter sometimes in all stages, and 
sometimes only in a certain stage. 
The time of transformation to adults 
is generally in the spring, but it varies.” 
Thus the first adults emerged from the 
cages containing the infested lumber 
during the early part of February. 
Probably the adults of Tarsostenus 
univittatus emerge about the same time 
as those of their host, Lyctus plani¬ 
collis , for Snyder (5, p. 14, 4) records 
that adults of the latter emerged as 
early as January 12 in a heated build¬ 
ing in the vicinity of Washington, D. C., 
that their general appearance occurs 
about the middle of April, the maxi¬ 
mum emergence from the last of April 
to the first of June, and the last emerg¬ 
ence during the first part of July. 
All these data coincide with correspond¬ 
ing data for Tarsostenus univittatus , 
as far as observations have been made. 
The mating usually occurs shortly 
after the adults emerge. 
OVIPOSITION 
Oviposition begins a day or two after 
the adults emerge from the wood and 
mate. The beetles were observed to 
crawl into the entrance galleries of 
their host, and it is likely that eggs 
were deposited there. According to 
Champlain ( 1) “they may be placed 
in or near the entrance gallery of their 
1 Received for publication April 22, 1924—issued—January, 1925. 
2 Reference is made by number (italic) to “ Literature cited,” p. 51. 
8 Order Coleoptera, family Cleridae. 
4 That the larva does not confine itself to attack on a single host is suggested by the observations of 
the present writer, who saw a mature larva in rearing crawl over the surface of the wood and enter 
a gallery of Lyctus from which powderlike borings were being ejected. Altogether, a large percentage 
of their host must have been killed by the attacks of the beetle, both in the larval and adult stages. 
Journal of Agricultural Research, Vol. XXli No. 1 
Washington, D. C. July 1, 1924 
Key No. K-137 
99178—25t-4 
(49) 
