BEUTENMULLER, MONOGRAPH OF THE SESIIDyE. 247 



Memythrus tricinctus {Harris). 



Plate XXXIII, Fig. 9, Female. 



ALgeria tricincta Harris, Am. Jour. Arts and Sciences, Vol. XXX, 1839, p. 310; Walker, Cat. 

 Lepid. Brit. Mus. Pt. VIII, 1856, p. 41 ; Kellicott, Bull. Buffalo Soc. Nat. Sc. Vol. IV, 

 1882, p. 62 ; Packard, Ins. Inj. Forest and Shade Trees (Bull. 7 U. S. Ent. Com.), 1881, 

 p. 121 ; 5th Rep. U. S. Ent. Com. 1890, p. 444 ; Kellicott, Can. Ent. Vol. XIII, r88i, 

 p. 3; Fyles, Can. Ent. Vol. XVI, 1884, p. 223; Rep. Ent. Soc. Ontario 1884 (1885), 

 p. 24. 



Trochilium tricincta Morris, Synop. Lepid. N. Am. 1862, p. 138. 



Sesia tricincta Boisduval, Suites a Buffon, Nat. Hist. Lepid. Het. 1874, p. 436. 



Sciapteron tricincta Grote, New Check List N. Am. Moths, 1882, p. 11 ; Davis, Ins. Life, Vol. IV, 

 1891, p. 66 ; Kellicott, Can. Ent. Vol. XXIV, 1892, p. 209 ; Ins. Life, Vol. V, 1892, p. 

 82 ; Beutenmuller, Bull. Am. Mus. Nat. Hist. Vol. VIII, 1896, p. 120 ; ibid. Vol. IX, 

 1897, pp. 213 and 218. 



Male. — Head black, collar yellow in front and at each side behind ; palpi black, yellow inside 

 towards the tip. Antennae blue black above, ferruginous beneath. Thorax black, with a yellow 

 spot at the base of the fore wings and one on each side posteriorly. Abdomen black, with a slight 

 bluish reflection. Second, fourth, and last two segments with a yellow band above and below. Anal 

 tuft black. Legs black, middle and hind tibiae partly orange, the latter yellow inside ; tarsi orange. 

 Fore wings opaque, violet black with a short transparent streak at the base ; inner margin streaked 

 with red at the base, sometimes also along the costa for a short distance ; underside yellow at the 

 base. Hind wings transparent, with a narrow outer margin and discal mark violet black, as are also 

 the veins. Underside with discal mark and costal margin orange red or same as above. 



Female. — Like the male, but with only three yellow bands on the abdomen instead of four, 

 one on each of the second, fourth, and sixth segments. 



Expanse : Male and female, 25-28 mm. 



Habitat. — Canada, New England, and Middle States westward to Ohio and Michigan. 



Type : One male, Coll. T. W. Harris, Boston Soc. Nat. Hist. 



Larva. — " Normal (S. exitiosa), the epicranial lobes broadly contiguous for a space equal to three 

 times the width of the paraclypeal pieces ; clypeus with the lower angles broadly truncate ; paracly- 

 peal pieces broadest below, not strongly defined. Head luteous, mottled with large patches of 

 brown ; labrum, band over epistoma, and sutures of clypeus black. Body fleshy white, smooth, the 

 annulets though present, not sharp ; subventral folds distinct. Cervical shield faintly luteous, the 

 curved line brown ; anal flap very faintly luteous with a subdorsal brown tubercle. Tubercles 

 nearly obsolete, setae short. Feet with 18 to 22 crochets in a row."— (Dyar, MS.) 



This species may be easily recognized by the opaque, purplish fore wings 

 and yellow bands on the abdomen. In the larval stage it lives in the branches 

 and small trunks of willows and poplars and also in the galls of Saperda concolor 

 which infest these trees. The channel made by the larva is from three to five 

 inches long, two larvae often being in one channel. The larvae before transforming 

 prepare a way for final escape, which they carefully guard by means of a silken 

 membrane, reinforced by fragments of wood. They then line the burrows near 

 the entrance with silk and spin a tough cocoon composed of silk and chips of 

 wood. The moths emerge during June and July and the larvae overwinter in the 

 food-plants, forming chrysalids in May and June. 



