BULLETIN 443;, U. S. DEPARTMENT OF AGRICULTURE. 



NATURAL ENEMIES OF THE RANGE CATERPILLAR. 



Several kinds of natural enemies native to New Mexico are destroy- 

 ing the range caterpillar. To help these native forms, other kinds of 

 natural enemies have been introduced. 



NATIVE NATURAL- ENEMIES. 



A small percentage of range caterpillar eggs is destroyed by a four- 

 winged, wasphke internal parasite. Two kinds of two-winged flies 



resembling house flies 

 or blowflies lay their 

 eggs upon the caterpil- 

 lars, and the maggots 

 hatching from them act 

 as internal parasites, 

 devouring the flesh and 

 ^'insides" of the cater- 

 pillars. One of these 

 flies is illustrated in fig- 

 ure 10. Furthermore, 

 three kinds of wasplike 

 internal parasites, one 

 of which is shown in 

 fig-ure 11, have been 

 found to destroy the 

 pupae. The effective- 

 ness of such parasites 

 in different localities 

 varies from less than 1 

 to as much as 75 per 

 cent of the caterpillars 

 and pupae present. 



Skunks eat great 

 numbers of range cat- 

 erpillar pupae and have 

 been the means of prac- 

 tically exterminating the pest over certain areas. During the autumn 

 season about 85 per cent of the food of the skunk, in the infested 

 region, consists of these pupae. This animal is very valuable as a 

 destroyer of insects. 



Badgers, coyotes, mice, and robins also feed upon the range cater- 

 pillar in its various stages. Several kinds of large ground beetles, 

 some of the large ants, and robber flies prey upon the pest. 



In some localities from 10 to 50 per cent of newly deposited eggs 

 are destroyed by two different kinds of camel crickets. 



Fig. 9.^— Male moths of the New Mexico range caterpillar resting 

 during the day on stem of wild smiflower. (C. N. Ainslie.) 



