June. 1904.] Davis : Caterpillars Attacked by Histers. S9 



reserve, others state that Histers are found about decaying substances, 

 under bark and in ants' nests without saying what they feed on. In 

 the Cambridge Natural History Dr. Sharp writes: " Formerly it was 

 supposed that the insects were nourished on the decaying substances, 

 but it is now believed, with good reason, that they are eminently 

 predaceous in both larval and imaginal instars, and devour the larvae 

 of Diptera, etc." Ganglbauer fills in this "etc.," as far as cater- 

 pillars are concerned, by saying that the European Hister pusfulosus 

 attacks the caterpillars of Agrotis. 



On May 29, 1903, when several of the members of the New York 

 Entomological Society were at Fort Montgomery, on the Hudson, 

 we walked along a woodpath at the base of Bear Mountain. There 

 was but a subdued light, as the woods were thick and the morning 

 cloudy. At the base of a large tree I discovered a caterpillar (an im- 

 mature noctuid larva) about an inch long that had been seized on its 

 back near its anal extremity by a Hister, which has since been identi- 

 fied as H. interniptiis Beauv. The beetle's jaws were firmly fastened 

 into the caterpillar, which was making off as fast as possible, but now 

 and then turning on the Hister and struggling hard to free itself. We 

 watched these struggles for some time, and then bottled the insects 

 for future identification. 



This is the only instance in which I have observed the predaceous 

 habit of Hister, but I have found the following American records 

 bearing on the subject. 



In Eutoniologica Americana for August, 1889, Mr. Charles Liebeck 

 writes of a collecting trip at Westville, N J. He says: "On the 

 same day I noticed an unusual carnivorous inclination on the part of 

 a single Hister biplagiatus. Its victim was a smooth caterpillar about 

 one and one quarter inch long, which it had seized on top of the 

 second segment, burying its head beneath the skin, after the manner 

 of a tick. For fully fifteen minutes I watched them, during which 

 time the unlucky caterpillar's frantic struggles failed to dislodge its 

 assailant, who never once relaxed the grip of its jaws. By this time 

 the caterpillar was covered with the juice oozing from its wound, and 

 having satisfied myself of the intention of the Hister, I consigned 

 them both to the alcohol bottle for future reference. My j^revious 

 knowledge of the habits of this Hister has been confined to the drop- 

 pings around pig-pens, where it may possibly feed upon the numerous 

 larvae found in such places." 



