90 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



THE ATTACK OF A LARVAL HEMIPTER UPON A 

 CATERPILLAR. 



BY F. ALEX. MCDERMOTT. 



The following observation is not claimed as especially new 

 or remarkable, but presents some interest as a study of insect 

 tactics. 



Upon the trunk of a large poplar which was thickly beset 

 with the tents or webs of Hyphantria cnuea, I observed a 

 larval hemipter, probably of the genus Podisns, with his beak 

 extended and the point penetrating the side of one of the 

 caterpillars inhabiting the nests. The caterpillar attacked 

 was dead and quite limp, evidently being pretty thoroughly 

 sucked out. With some difficulty I succeeded in separating 

 the hemipter from his prey, though he was very loath to part 

 with it, and held on like the proverbial bulldog. When first 

 disturbed the hemipter ejected from the anal glands three 

 drops of clear fluid which may have had an odor, although I 

 could not detect it in the open air. 



After removing the first caterpillar I secured a second fresh 

 specimen of the same species, and placed it on the trunk near 

 the hemipter. The latter immediately showed a fresh interest 

 in proceedings and trailed the caterpillar up the bark, with 

 his beak extended and close to the surface, as if following the 

 "scent." Twice he ran alongside of the caterpillar, getting 

 as close as the latter's hair would allow him, and inserted his 

 beak beneath the caterpillar, evidently trying to puncture the 

 abdomen. In both of these instances the caterpillar snapped 

 its head around and the hemipter retreated rapidly, evidently 

 fearing the caterpillar's jaws. On 'the third attempt he suc- 

 ceeded in inserting his beak through the skin, and though 

 the caterpillar squirmed and snapped back for a few seconds, 

 he did not release his hold. The caterpillar seemed to accept 

 its fate after a few moments, perhaps poisoned by the hem- 

 ipter, for it ceased to wriggle and twist. When placed in a 

 test-tube the hemipter released his hold and the caterpillar 

 crawled off as if uninjured, but it died shortly afterward. 

 Later a smaller larva of the same species of hemipter was 

 found holding a smaller caterpillar of the same species. 



On account of the long time required for one hemipter to 

 secure his meal from these caterpillars, it seems hardly likely 

 that the pentatomid would prove very effective as a check to 

 the prevalence of the webworm, though those observed were 

 certainly doing their best to reduce the number. In captivity 

 the hemipter shows a disinclination to feed, and the caterpillars 

 did not show any especial dread of their enemy. 



