88 BULLETIN 190, UNITED STATES NATIONAL MUSEUM 



stalked. Posterior tibiae roughly scaled above; first tarsal joint thickened 

 with rough scales above. Male genitalia with short, stout (often paired) 

 cornuti, saccnlus ridge with flat scales in a dense, obliquely curved line. 

 Female genitalia with outer end of ductus bursae sclerotized. Anal tuft 

 in male wedge-shaped. 



The American species placed in this genus, aside from structural similari- 

 ties, have much in common with the biological characteristics of the geno- 

 type, vespijormis, of Europe. The sacculus ridge of the male genitalia in 

 the American species shows flat scales in a less dense arrangement, curved 

 outwardly, differing in this respect from vespijormis. Most of the Ameri- 

 can species, as here limited, are borers in oak, normally attacking the 

 bark, but specimens found in greatest abundance in abnormal swellings due 

 to cankerous growth and, in particular, in woody galls of cynipid origin, 

 which they occupy as commensals. There are other generically distinct 

 species sharing such habits; from these the species of Synanthedon are 

 distinguished by the thickened posterior first tarsal joint and by the wedge- 

 shaped male anal tuft. 



The genotype is figured on plate 1, figure 8; plate 6, figures 3S, 35a; 

 and plate 13, figure 65. 



SYNANTHEDON SAPYGAEFORMIS SAPYGAEFORMIS (Walker) 



Acgeria sapygaeformis Walker, List of the specimens of lepidopterous insects in 



the collection of the British Museum, pt. 8, p. 45, 1856.— Hy. Edwards, Papilio, 



vol. 1, p. 207, 1881. 

 TrochiUum sapygaeformis Morris, Synopsis of tlie described Lepidoptera of North 



America, p. 333, 1862. 

 Sesia sapygaeformis Boisduval, Histoire naturelle dcs insectes : Species general des 



lepidopteres heteroceres, vol. 1, p. 440, 1874. 

 Pyrrhotaenia sapygaeformis Grote, New check list of North American moths, p. 12, 



1882.— Beutenmuller, Bull. Amer. Mus. Nat. Hist., vol. 8, p. 146, 1896. 

 Sesia sapygaeformis Beutenmuller, Mem. Amer. Mus. Nat. Hist., vol. 1, pt. 6, 



p. 310, 1901. 

 Synanthedon sapygaefonnis McDunnough, Check list of the Lepidoptera of Canada 



and the United States of America, pt. 2, No. 8753, 1939. 



Male. — Antennae robust, strongly dilated, bipectinate. Labial palpi 

 long, ascending, curved, deep orange, bases and sides black. Head black, 

 covered with strong violaceous scales. Collar red. Thorax densely hairy, 

 black, conspicuously bordered with red posteriorly above ; beneath marked 

 with red before the wing base. Abdomen lustrous black, segments 4, 5, 6, 

 and 7 red above and beiieath ; anal tuft wedge-shaped, black. Legs viola- 

 ceous, marked with orange ; hindtibiae twice broadly banded with orange ; 

 first tarsal joint thickly scaled, black and orange. Forewing very nar- 

 row, widening at outer third, which is blackish violaceous ; the narrow por- 

 tion of the wing medially orange-red, with radiations beyond the deep red 

 cell; clear spaces reduced to an intervenular short streak from the wing 

 base ; underside largely shaded with orange, radiating into the outer margin. 



