1941] 
Life-cycle of Tetraopes tetrophthalmus 
169 
A NOTE ON THE LIFE-CYCLE OF TETRAOPES 
FEMORATUS LECONTE 
(CERAMBYCHLE) 1 
By R. W. Williams, 
University of Illinois 
While making a study of the bionomics of the common 
milkwood beetle, Tetraopes tetrophthalmus (Forst.), during 
the summer of 1940 at Urbana Illinois, I found, on August 
11, a fully developed Tetraopes larva tunneling through the 
center of the horizontal root of the common milkweed, 
Asclepias syriaca. This larva was identified at the United 
States National Museum as being different from those 
thought to be T. tetrophthalmus. Unfortunately the species 
could not be determined since investigators had never asso- 
ciated larvae similar to this one with an adult beetle. Since 
tetrophthalmus and femoratus were the only species of 
Tetraopes seen during my observations I believe that this 
single specimen was a representative of femoratus. The size 
of the individual would also warrant this conclusion since 
the adult of femoratus is the largest species of Tetraopes 
found in the state. This specimen was 23 mm. in length. 
Larvae of T. tetrophthalmus, which were found during the 
fall of 1939, ranged from 13 to 19 mm. in length. 
The first adult of T. femoratus was seen on July 23. It 
seemed highly improbable that eggs could have been de- 
posited and the larvae from these eggs could have reached a 
fully developed condition within a period of twenty days or 
even a month, assuming that the adults were present earlier. 
These facts, therefore, seem to indicate that at least some 
individuals of this species may spend two or more years in 
the larval condition about the roots of milkweed. Since the 
roots of these plants are perennial the larvae would have a 
^Contribution No. 220 from the Entomological Laboratories of the 
University of Illinois. 
