THE ALFALFA CATERPILLAR. 7 
or, perhaps, have passed into the pupal stage before the crop is 
cut off. 
Many fields observed by the writer were attacked in strips or 
patches. Sometimes one border would be almost totally devoured, 
while an adjoining plot would not be molested. Again, in other 
fields irregular patches would be attacked and the rest of the field 
not materially injured. In cases where whole borders of alfalfa 
were injured, the time and amount of water applied in irrigating 
produced an uneven growth, and as the generation of butterflies, on 
issuing, chose for egg-laying the strip that was the greenest and 
freshest, this strip would be the one damaged. It seems possible to 
account for the irregular patches in the same way—that is, consider- 
ing that these patches were ones that were held back because of the 
condition of the soil. The soil conditions in one part of the field 
may be quite different from those in another part of the same field, 
and thus a varying growth of the crop results, which would be at- 
tacked in patches. 
FOOD PLANTS. 
Besides alfalfa the larva is known to feed upon the two buffalo 
clovers, Trifolium reflecum and T.. stoloniferum, which probably con- 
stitute its original native food plants. It also feeds upon white clover 
(7. repens), and in California on 7. tridentatum, but is said not to 
attack red clover (7. pratense). Other food plants noted by Scudder 
are Hosackia, ground plum (Astragalus caryocarpus), and A. crotal- 
arie. The butterfly is known to oviposit on Afedicago hispida, and at 
Indio, Cal., on July 1 the writer found larvee feeding on sweet clover 
(Melilotus alba), which strangely enough they seemed to prefer to a 
patch of alfalfa growing close by. Eggs were also observed to be 
very numerous upon the leaves of the sweet clover at the same time. 
INSECT ENEMIES. 
The white eggs of tachinid flies were always in evidence wherever 
any larve were to be found, and the young of these destroy quite a 
large number of worms. In one instance it was noted that as many as 
15 per cent of the worms had tachinid eggs on them. Because of the 
supposedly contagious disease, as shown in a following paragraph, 
little success resulted from rearing these parasitic flies. Five speci- 
mens were reared from the larve of Eurymus. These were all of the 
species Luphorocera claripennis Macq. (fig. 6). One specimen, de- 
termined by Mr. D. W. Coquillett,of this bureau,as Jfasicera sp., was 
reared from the pupa of Eurymus. 
Two species of hymenopterous parasites were reared. From the 
Eurymus larve several specimens of Zimnerium sp.—all females, how- 
[Cir. 133] 
