4 BULLETIN 1238, U. S. DEPARTMENT OF AGRICULTURE 



were later (£6) shown to be synonyms of vernata Peck and pome- 

 taria Harris, respectively. 



The two species were clearly distinguished in 1873, when Mann 

 (15) indicated the differences between the adults of the two species, 

 but owing to a lack of clearness in the language which had been used 

 by Harris, he reversed the intended application of the specific names, 

 calling the fall species vernata and the spring form pometaria. His 

 attention was soon called to the error, and in a communication pub- 

 lished January 1, 1874 (16) , he corrected it, giving the specific names 

 to the respective forms as we know them to-day. He also dis- 

 tributed a correction slip to be inserted with the original account. 

 The following year, in his annual report for 1874, Riley (17) car- 

 ried the* distinction still further, differentiating between the two 

 species in all stages, and illustrating the differences by figures. The 

 same year he erected a new genus for vernata (18), and since that 

 time the spring cankerworm has been generally known as Palea- 

 crita vernata (Peck). In spite of the efforts made by Mann to 

 correct his error, and in spite of the publication of Riley's account, 

 the confusion caused by the misinterpretation of the language used 

 by Harris persisted for several years, and in 1876 Packard (19) 

 suggested for the fall species the name autumnata to replace pome- 

 taria Harris, which he thought had been applied by Harris to the 

 spring species. This change was soon shown to be unnecessary. 



The species pometaria was placed in the genus Alsophila by Hulst 

 (£7) in 1896, and since then no change has been made in nomencla- 

 ture. 



In 1901, -Dyar (%9) published detailed technical descriptions of 

 the egg and larval stages of the fall cankerworm, and in 1902 (30) 

 he published similar descriptions of the spring species. 



SYNONYMY. 



Paleacrita vernata (Peck). 



Phalaena vernata Peck, 1795, in Mass. Mag., v. 7, Nos. 6 and 7, p. 323-327, 



415-416. 

 Geometra vernata (Peck) Harris, 1830, in New England Farmer, v. 9, No. 1, 



p. 1-2. 

 Anisopteryx vernata (Peck) Harris, 1841, in Harris, Injurious Ins. Mass., p. 



333. 

 Anisopteryx serieeiferata Walker, 1862, in Cat. Brit. Mus., pt. 26, p. 1697. 

 Paleacrita vernata (Peck) Riley, 1785, in Trans. Acad. Sci. St. Louis, v. 3, 



p. 573-577. 



Alsophila pometaria (Harris). 



Anisopteryx pometaria Harris, 1841, Injurious Ina. Mass., p. 333. 

 Anixopteryx restituens Walker, 1862, in Cat. Brit. Mus., pt 26, p. 1696. 

 Alsophila pometaria (Harris) Hulst, in- 1896, Trans. Amer. Ent. Soc, v. 23, 



Hay den), v. 10, p. 400. 

 Alsophila pometaria (Harris) Hulst, 1896, in Trans. Amer. Ent. Soc, v. 23, 



p. 257-258. 



COMMON NAMES. 



Cankerworms belong to that group of lepidopterous larvse vari- 

 ously known as inchworms, measuring worms, spanworms, or 

 loopers. The name cankerworm originated several centuries ago, 

 and was used in Europe for a number of different species of cater- 

 pillars. In America the term cankerworm has been used for the 

 most part in reference to the two species here discussed, although 



