200 Bulletin 396 



of the leaves, and feed on the tender foha<j;e and to a sH<:;ht extent on 

 the fruit before reaching maturity. In a few cases the adult bugs have 

 been observed to feed on the fruit, but all fruits so attacked dropped 

 within a short time. It is apparent that in the case of most varieties 

 of apples the bugs have practically finished feeding before the fniit is 

 large enough to withstand the injuries that may be produced by them. 



In trying to get definite data on the work of this species, the writer in 

 19 1 5 carried out no less than forty experiments, each of which consisted 

 of isolating two fourth- or fifth-stage nymphs on an apple branch which 

 was blooming and setting fruit. The nymphs invariably preferred to feed 

 on the tender foliage instead of on the fruit. The few fruits that were 

 injured by the bugs did not survive the June drop and thus were lost. 



The adults of this species (fig. 45) are mature and have begun to lay 

 eggs by the time the fruit is large enough to be injured, and thus its 



opportunity for doing harm is not so great as 



is that of Lygidea mendax. Redbug injur\^ on 



Twenty Ounce apples, which developed on a 



tree infested by H. malinus and which the 



writer believes to be the work of this species, 



is shown in figure 46. The Twenty Ounce and 



pippm apples are, by the nature of their rapid 



Jw development, the most likely to attain the size 



m ^ necessary to withstand the feeding punctures 



Ik M J^L of the bug and thus to i3roduce mature scars 



^^^^^Hfttf from this species. It appears quite certain that 



in western New York the work of H. malinus 



Fig. 45. ADULT OF HETERO- . , . , t.^ c ■ ■>- ■ T i J 



CORD YL us MA LIN US ON ^^ pToducmg knotty fruit is very limited or en- 

 YouNG APPLE tircly absent on the standard varieties of apples. 



OTHER SPECIES 



The writer has made extended observations also on the work of 

 Paracalocoris hawleyi Knight (variety) and Neurocolpus nubihis Say. 

 both of which may be found breeding on apple. In all cases, however, he 

 failed to find injury resulting on the fruit. 



WARTING OF SCARS 



Two Rhode Island G'r^^Mtwg apples are shown in figure 47, and a Tol- 

 man apple in figure 48, which were all injured by redbugs but which late 

 in the season forced new growth thru the russet scars and thus not only 

 filled out the depressions but actually produced elevations. The writer "has 

 seen this warting produced in scars made by redbugs, curculios, fruit-tree 

 leaf-rollers, green fruit-worms, tussock moths, ai)])le scab, and frost injury. 



310 



