250 
Psyche 
[June-September 
the use of a fine camel-hair brush, together with five immature 
aphids. After moulting to the second instar and thereafter the larvae 
were provided thirty aphids per day. Following the third molt the 
new fourth instar larvae were used for experimentation. 
To study searching behavior before and after feeding, an artificial 
searching arena was constructed similar in design to the arenas of 
Fleschner (1950) and Banks (1957). A twelve inch square plywood 
board was covered with buff-colored art paper and surrounded by 
an electrically heated wire. The arena was uniformly illuminated by 
a fluorescent light suspended two feet above the center, and all tests 
were performed at room temperature. Tracks of the larvae were 
recorded by tracing lightly with a pencil, and 30 sec intervals were 
noted on the tracks. Track diagrams were enlarged with an over- 
head projector. The number of degrees of each turn, whether to the 
right or left, was measured with a protractor. The data were 
expressed as the total number of degrees turned, which was a 
function of the number and type of turns the larvae made. Statistical 
analysis was done with Student’s t-test. 
Results 
Sixteen fourth instar H. convergens larvae were starved for 4 hrs 
prior to testing. Each larva was placed in the center of the arena 
under a vial, and timing commenced when the vial was removed. 
The larva was followed by a pencil tracing and 30 sec intervals were 
recorded on the track for a total test period of 5 min. At this time an 
adult T. maculata was placed directly in front of the larva; the aphid 
was seized and rapidly consumed. The track was again traced when 
the larva began to move after feeding, and 30 sec intervals were 
recorded for 5 min. This test procedure was repeated for each of 
sixteen larvae. 
The movements of larvae before feeding were less tortuous and a 
much larger portion of the arena was searched; after feeding the 
larvae concentrated their search in the vicinity where the aphid was 
discovered. The track consisted of numerous turns and frequently 
areas previously searched were revisited several times. Analysis of 
the tracks confirmed these observations (Fig. 1). For three minutes 
following the consumption of an aphid the larvae made more turns 
than they did prior to feeding, but in the final two minutes of 
observation the fed larvae appeared to revert to their pre-fed 
