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SEVENTH ANNUAL REPORT 



CANKER-WORMS. 



la further illustration of the remarks made last year on the two 

 species of Canker-worm which have very generally been considered 

 mere varieties of one species, and about which there has been no little 

 confusion,* I have prepared figures of each, which, in connection with 

 a few explanatory remarks, will enable their ready distinction. 



[Fig. 14.] ^ijij. Spring Canker-worm {Anisopieryx vernata^ 



Peck, Figs. 14, 16. This species, which, from the 

 fact that the great bulk of the moths issue from 

 the ground in early spring, may be distinguished 

 from the other by the popular name here given, 

 springCanker-wokm:— a, fuiiis the truo Canker- woriTi originally described^ 



grown larva ; h, ^%%, enlarged, 



the natural size shown in the as P^aZce;i« vemata by W. D. Pock in 1795. 



small mass at siile;f, an enlarged ^</w ^ ^^ j 



'y^^,tho^Ji:'^iiemJk(.^sr^'^\^'^^ is undoubtedly the species for the most 

 part spoken of in the agricultural journals of the country, and the 

 species best known in the Mississippi Valley.f This Spring Canker-worm 

 is distinguished, in the light of recent careful discriminations, by the 

 characters indicated last year, viz.: by each of the first seven joints of 

 the abdomen in both sexes bearing two transverse rows of stiff, red, 

 or reddish-brown, posteriorly directed spines ; by the front wings in 

 the male having three transverse, dusky lines, and a somewhat broader, 

 jagged, pale submarginal line ; and by the whole body in the female, 



* This confusion is in part due to the fact that Harris, in his work on Injurious Insects, in treating 

 of THE Canker-worm moth, describes at length, not the species fii-st called the Canker-worm by Peck, 

 but the larger species (pometaria) . lie then uses the following language: "Specimens of a rather 

 smaller size are sometimes found, resembling the figure and description given by Prof. Peck, in 

 -which the Avhitish bands and spots are wanting, and there are three interrupted, dusky lines acros? the 

 fore- wings, with an oblique, blackish dash near the tip. Perhaps they constitute a diUerent specie.s 

 from that of the true Canker-worin moth. Should this be the case, the latter may be called Anisopteryx 

 pometaria." The term " true Canker-worm " is here misleading, as, while it should evidently apply 

 to the insect originally described by Peck, Harris really applies it to the other species, for whichhe sug- 

 gests the name jaomc^aria. It is this ambiguity which originally led Mr. Mann to confound the two 

 species, and which led me to make the remarks in the first paragraph on page 29 of my last Report, 

 which— founded on a misunderstanding of Harris's meaning— should be cancelled. As I have already 

 stated, the descriptions in my Second Report are of vemata, but the poor figures, which are copied, 

 represent neither species properly, though those of the moths are of vemata and those of the eggs 

 pometaria. Harris's descriptions of the moths and eggs are oi pometaria, but those of the larva, and 

 probably of the chrysalis, are of vemata. 



t There is in fact no evidence that the other species /Jonie/aci'a occurs at all either in Illinois or Mis- 

 souri, since an examination of the specimens in Br. LeBaron's cabinet and in my own, proves them 

 all to be tlieti-ue or Spring species. Indeed, until I received specimens oi pometaria from Mr. H. K. 

 Morrison and Mr. B. P. Mann, I had never seen the species— the male specimens which 1 mistook for it 

 in former years being in reality specimens of ■ye/na<a which approach it in the markings of the front 

 wings. That it occurs in the Southwest is, however, proved by the fact that Dr. Packard informs me 

 that he has a fine typical specimen from Dallas, Texas, collected by Mr. Boll. 



