THE CANKERWOKMS 3 



occurred at intervals in various parts of New England. In Con- 

 necticut, the " cankerworm years " have occurred during the follow- 

 ing periods : 1838-1846, 1866, 1884, 1896-1900, and 1907-1909. The 

 fall cankerworm seems to be on the increase at the present time 

 (1921) in the State, although it is impossible to predict when the 

 infestation will become severe enough to constitute an outbreak. 



The history of the cankerworms in other sections of the country 

 has been similar in many ways to that recorded for New England, 

 consisting of successive outbreaks varying in extent and severity, 

 alternating with periods of comparative scarcity. 



In the Middle West, practically all records refer to the spring 

 species. The history of the cankerworm in this section begins in 

 1852, with an outbreak in Illinois, which lasted from that date until 

 1860, in which year the worms suddenly disappeared. Severe out- 

 breaks of the spring cankerworm have been reported at intervals in 

 practically all States of the Mississippi Valley from Arkansas north. 



Kansas has suffered outbreaks of the spring cankerworm during 

 the periods 1879-1886, 1896-1899, and 1913-1917. 



Both species have been known for many years in southern Canada, 

 the fall form being most abundant and widespread, but the infesta- 

 tions in most cases do not seem to have been as severe as many of 

 those occurring in the Mississippi Valley and in New England. The 

 fall cankerworm has done considerable damage in Nova Scotia in 

 recent years. 



Neglected orchards in northern Virginia were badly infested by 

 the spring species for several years previous to 1907 (32). 



The fall cankerworm was reported from California in 1891, and 

 later the spring species was also found. Since that time several out- 

 breaks have occurred, and considerable damage has been done in the 

 apple-growing regions of the central and northern parts of the 

 State. 



Local outbreaks of the fall species have been in progress in forest 

 areas in the mountains of North Carolina since 1917, and a serious 

 infestation of both species, the spring cankerworm especially, was 

 reported from Wisconsin in 1921. 



SCIENTIFIC HISTORY. 



As already noted, the name given to " the " cankerworm by Peck 

 in 1795 was PhaZaena vernata, his description applying almost en- 

 tirely to the spring form. In several accounts published between 

 1830 and 1841, the cankerworms were mentioned by Harris and 

 others as Geometra vernata. In 1841, in his Eeport on the Insects 

 of Massachusetts Injurious to Vegetation, Harris (9, p. 333) placed 

 them in the genus Anisopteryx. At the same time he noted that 

 two types of moths were found, and suggested that there might 

 be two species involved. Should this be the case, he said, the latter 

 may be called Anisopteryx pometaricL, or the Anisopteryx of the 

 orchard, while the former should retain the name originally given 

 to it by Professor Peck. 



More than 30 years elapsed before the existence of two species 

 was generally recognized. 



In 1862, Francis Walker (11) described two American species 

 of Anisopteryx which he called sericeiferata and restituens. These 



