88 MAINE AGRICULTURAL EXPERIMENT STATION. I9I5. 



factor in the growth of this timber tree. The insect acquires its growth 

 in the early part of the summer and mainlj^ disappears by the middle of 

 August. 



Oncopsis fenestratus Fitch 



Athysanus fenestratus Fitch Homop. N. Y. State 'Cab. p. 60, 1851 



Bythoscopus fenestratus Van Duzee Entom. Amer. VI 226, 1890. 



Grayish brown with whitish hyaline spots on the elytra and dark patch 

 on the front. About 4.5 to 5 mm in length. 



This species has been taken in considerable numbers chiefly from 

 birch but specimens referred here are from willows also, though birch 

 would seem to be the main food plant and the one on which it would 

 have the most importance. On Mt. Katahdin it was found at various 

 altitudes and one specimen evidently belonging here was collected near 

 the summit, 4,500 ft. probably from the scrub willows. 



Oncopsis minor Fitch. 



Bythoscopus minor Fitch Homop. State Cab. p. 60, 1851. 



Bythoscopus minor Van Duzee Entom. Amer. VI 228, 1890. 



'Specimens referred here resemble fenestratus but are smaller and 



agree well with Van Duzee's description. They are gray brown, the 



elytra in the female almost entirely hyaline and in the male clouded with 



tawriy brown. Length 4 mm. 



Larvae taken in association with males on birch June 11, 1913, and 

 probably belonging to this species are uniformly brown. 



Oncopsis variabilis Fitch. 



Athysanus variabilis Fitch. Homop. N. Y. State Cab. 1851, p. 60; 

 reprinted in Lintner 9th Rep't 1893, p. 400. 



An extremely variable species occurring abundantly during spring 

 and early summer on birches. A common variety is sulphur yellow 

 with more or less of black on the elytra most commonly as a line or 

 stripe along the claval suture. Length 5-6 mm. 



Our collections represent Orono, particularly June 3 to Aug. 6, as 

 the species does not persist through the summer and it had disappeared 

 by the time our collections were extended to other parts of the state. 

 I have a record for Mt. Katahdin (H. G. Barber) and specimen in 

 Boston Soc. N. H. are from Calais and Eastport (C. W. Johnson). It 

 must occur over a large part of the state and its attacks on the birch 

 must be a source of injury, 



Oncopsis sobrius, Walk. 



Bythoscopus sobrius Walk. Homop. 1851. 3 : 874; Fitch, reprinted 

 in Lintner, 9th Rep't. 1893, P- 400; N. Y. State Agricultural Soc. Trans. 

 1858. 18 : 853. 



