484 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



numbers the birds that come first as insect feeders in Panama are a 

 species of blackbird, but it is not likely that more than a small per- 

 centage of each season's brood are destroyed by birds. 



As lizards are insectivorous in their feeding habits to a large extent, 

 is reasonable to suppose that they also destroy many of the young 

 caterpillars by eating them while they are on the ground and also 

 while they are in the trees and before becoming too large, as several 

 varieties of lizards are often to be found in the trees seeking for insects 

 to feed on. 



The caterpillars are nocturnal and are most active at night-time, 

 or while in dark places, and it may be supposed that many of the 

 young ones that emerge from eggs away from the trees, and while 

 endeavoring to reach the trees, and also many of those that are full 

 grown after leaving the trees and while on the ground seeking a place 

 to pupate, fall an easy prey to toads, as they are very numerous in 

 this region, and are both insect feeders and feed largely at night as well. 

 Toads that were in captivity ate eagerly of half-grown caterpillars 

 when given to them. 



Parasitic insects undoubtedly destroy a larger percentage of B. 

 isthmia than any of their enemies just mentioned and may be classed 

 as second in importance of their natural enemies as a control of this 

 pest. These parasitic enemies destroy the B. isthmia while they are 

 in the chrysalis stage. Some of the parasitic flies deposit their eggs 

 or living larvae either on, or near enough to, the chrysalis so that the 

 young lai-vse may enter it without much trouble and feed on the soft- 

 bodied insect and destroy it. Other flies inject their eggs directly into 

 the chrysalis and the young larvae emerge from the eggs inside and 

 promptly proceed to devour their host. 



The adults of these parasites come under two orders, the Hymen- 

 optera or four-winged flies, and the Diptera or two-winged flies. The 

 small Chalcid flies are the principal hymenopterous parasites, and the 

 dipterous parasites belong to the SarcophagidcB and the Tachinidce. 



Unfortunately none of these parasites are peculiar to the B. isthmia 

 alone, they are simply accidental or occasional hosts, the flies selecting 

 them as food for their larvae as they might select chrysalids of many 

 other lepidoptera belonging to different families. 



It is to be deplored that the caterpillars have an opportunity to do 

 all their damage before pupating and allowing these parasites a chance 

 to get in their work, but at any rate they help to decrease the brood 

 the following year. 



The most important of all the natural enemies is a fungous disease 

 that attacks both the mature caterpillar and the chrysalis. This 

 fungi causes a high mortality among these pests every season, espe- 



