THE DOCK FALSE-WORM. 5 



larvae in the stalks of the orache (Atriplex nitens), and he states that 

 the larvae had undoubtedly fed on the pith, though he did not see 

 them doing so, and did not find them feeding on the foliage. The 

 writer has reared over a hundred and fifty larvae, and has seen them 

 bore into pithy stems, but in no case has he observed the last-stage 

 larva feeding on the pith or on anything else. The borings are 

 invariably pushed past the larva and fill up the burrow behind it. 

 (Fig. l,a.) 



In the course of the work with the dock false-worm, larvae and 

 adult males and females were confined with plants of the common 

 garden beet, with goosefoot (Chenopodium album), and with alfalfa, 

 since many prepupal larvae had been found in dry alfalfa stems. 

 The adult females in every case died without ovipositing, and the 

 larvae died without feeding on any of the plants, although larvae 

 transferred from one known food plant to another, as from dock to 

 wild buckwheat, readily adapted themselves to the change. 



In feeding on any of these plants, the larvae devour the leaf tissue 

 and the smaller veins, eating out irregular holes in the leaves. (PI. I, 

 fig. 2). Ordinarily, the midribs and the larger veins are untouched. 

 If forced to it, however, the larvae will feed on these, or even on the 

 stem, and sometimes also on the flowering parts. 



The dock false-worm must not be confused with the true apple 

 sawfly (Iloplocampa testudinea Cameron) of England, which has a 

 whitish larva that fives and feeds in young apples, its feeding habits 

 being similar to those of the related American species, the cherry 

 fruit sawfly (Iloplocampa cooTcei Clarke). 



CHARACTER OF INJURY TO APPLES. 



The dock false-worm is known to injure apples only in the fall, 

 when the fruit is approaching maturity; that is, in September and 

 October. In orchards under observation the larvae were present on 

 their food plants throughout the growing season, but no evidence 

 of injury was found that had occurred before the apples had practically 

 stopped growing, with one exception. A single Jonathan was found 

 < i October 5, into which a larva had succeeded in burrowing some 

 time before the apple had reached maturity. The apple had grown 

 subsequently and had closed the entrance and squeezed the larva 

 to death. The greater hardness of immature apples probably 

 deters the larva- from burrowing into them. There were no summer 

 apples in the infested orchards, hence it is not known whether these 

 are ever injured. 



The injury to apples consists externally of the small round holes 

 bored by the larvae, which after a few days show a slightly sunken, 

 brownish ring about them and occasionally may be surrounded by a 

 larger discolored halo. (PI. II, figs, i and 2.) These holes may 



