174 



FURTHER OBSERVATIONS ON THE PARASITISM OF DATANA ANGUSII^ 



Apropos to Mr. D. B. Wier's* criticism of a previous note of mine upon 

 this subject, I may state that while I did not observe caterpillars being^ 

 driven off the tree by Tachina flies, and was very careful not to say so» 

 nevertheless, I did think such was the case. 



The present season these larvae have occurred in greater numbers 

 than before for many years. The walnut tree, mentioned in my former 

 note, has been again denuded of its foliage, not a leaf being left on its 

 twigs or branches. The most critical search has failed to reveal a 

 single Tachinid about this tree, nor did an examination of several 

 hundred of the larvae develop a single individual, with the eggs on 

 its body. Another enemy to the pests entered the field, and, so far as^ 

 could be observed, held undisputed sway. This was an Ichneumon, 

 Anomalon relictum, and they were present in considerable numbers. 

 The oviposition of these last parasites was frequently witnessed, but the 

 parasitized host was seldom knocked or driven from the tree thereby. 

 The favorite method of attack appeared to partake of the nature of still 

 hunting, and, while isolated individuals were not ignored, particular 

 attention seemed to be paid to those caterpillars which were bunched 

 together on the trunk, in the act of moulting. From one to five of the 

 Anomalous were observed about these masses of helpless larvae, each 

 walking about in search of a favorable opportunity to place her egg in 

 the body of the host. If the eggs had been placed at random, those 

 on the outer side of the mass would have received them to the protec- 

 tion of those whose bodies were nearer the center of the mass. There- 

 fore, the parasites seemed to be on the watch for fresh hosts for their 

 young, and would edge up to the mass, as new forms were exposed, 

 and by throwing the abdomen beneath the thorax between the legs, 

 they would with the rapidity of lightning thrust the ovipositor into 

 the body of their victim, apparently without regard to locality. They 

 did not appear to possess any great amount of courage, for when a 

 larva made any movement, they quickly withdrew to a place of greater 

 safety.— F. M. Webster. 



BIRD enemies of THE COLORADO POTATO-BEETLE. 



In the report of the Ornithologist, Annual Eeportof the Department 

 of Agriculture for 1889, page 369, Dr. Merriam gives the following note : 



Further attention has been given to the bird enemies of the potato-bug, or Colo- 

 rado Beetle, and a few species beside the Rose-breasted Grosbeak have been found to 

 eat the pest occasionally. Among these is the Yellow-billed Cuckoo, already known 

 as a valuable friend of the farmer because of its habit of feeding upon caterpillars, 

 both smooth and hairy. With the Grosbeak the habit of eating potato-bugs proves 

 to be fairly constant, but unfortunately the bird does not seem to be very abundant 

 anywhere, and hence the resulting benefits have not been generally noticed. Some 

 of our correspondents have suggested that the scarcity of this bird, and perhaps of 



* Insect Life, Vol. 3, p. '26. 



