1328 Rocer C. SMITH 
even fail to fuse with it, as shown in Plate LX XVIII, 7. In such a case 
a very evident specimen of Chrysopa oculata might be placed in the 
genus Allochrysa by existing keys. A specimen of C. rufilabris was 
observed to entirely lack a median loop in one wing. But these varia- 
tions are unusual, and in the great majority of specimens the wing-vena- 
tional characters used by Banks and others in keys may be relied upon. 
In both wings, Cw arises as a separate vein. Soon after its origin 
in the front wing, a marked thickening occurs. There is nothing in the 
pupal tracheation that explains it. Cv, arises at this thickening and 
runs toward the margin, but branches slightly beyond half the distance 
to the margin. The main vein continues forward and gives off four 
branches to C, the anterior of which becomes Cu,. This differs from 
Tillyard’s interpretation, in that he has shown only three branches from 
the anterior branch of Cw to the margin, compensating by ealling R; 
three-branched at the tip. 
The short ecrossveins connecting the radial branches have been 
designated as gradate veinlets. The various genera differ as to whether 
there is one or two series present, and also as to the number in each 
series. 
Foods 
There has been some difference of opinion expressed in the litera- 
ture on the Chrysopidae as to wnether or not they take food. From the 
beginning of these studies, Chrysopa oculata, C. ngricorms, C. rufilabris, 
C. quadripunctata, and C. chi, were fed plant lice daily, which they ate 
very readily. The first two species listed were observed to eat them in 
their natural habitats. Any small aphids, young scales, and mites that 
happened to be available were given the chrysopids, and were readily 
eaten though not all were equally suitable in rearing work. A hungry 
adult of C. oculata was observed to devour seven cabbage aphids in 
succession. All adults apparently relished some water daily also. On 
the other hand, C. plorabunda was never observed to devour live 
aphids, though this species fed freely upon fluids of crushed aphids, 
weak sugar water, and plain water. Similar observations were made 
with C. harrisii, C. lineaticornis, and Allochrysa virginica. While these 
were offered various aphids, they were observed to feed only upon sugar 
water and water. It is thought that the proper food was not discovered, 
or that the insects may have fed during the night, rather than that they 
normally took no food. 
It can be readily observed that adults depend largely on tactile 
sensations, rather than on sight, to locate their food. The palpi are 
