AMERICAN LEPIUOPTERA. 325 



Family SPHINGIDAE. 



Tribe MdcrogJosaini. ■ 



SESIA, Fahr. 

 Sesia thetis. 



9. — Size and form of S. diiSiiis. Head, above, dull olivaceous; 

 eyes narrowly circled with white scales; labial palpi pale yellowish 

 beneath and on the sides, tinged with ferruginous inwardly, and with 

 superior, lateral, black scales tipping the terminal joint. Antennae 

 rather stout, blackish. Beneath, the thoracic parts are clothed with 

 pale yellowish scales, as are the anterior femora outwardly. Legs, 

 black. The thorax beneath is encroached upon centrally by the pale 

 pectoral scales, but is elsewhere black. Above, it is entirely obscure 

 olivaceous. Abdomen, above, black, shaded with brownish from over 

 the base downwardly; the two pre-anal segments are entirely pale yel- 

 low except centrally beneath, while dorsally the pale yellow scales are 

 narrowly tinged with brownish. Anal segmeu and tuft, black. Be- 

 neath black. 



Wings largely vitreous; anterior pair narrowly clothed with dark 

 brownish scales along costal edge; an unusually narrow, terminal band 

 tapering to internal angle; a basal scale patch below median nervure 

 outwardly obliquely on internal margin. Secondaries largely vitreous; 

 a very narrow, even, terminal, d^irk brownish edging; from the base 

 downward the internal margin is broadly clothed with dark scales. Be- 

 neath, as above ; the wings at base are partially clothed with pale yel- 

 low scales. 



Ujjxinse, 45 m.m. Length ofhodij^ 22 m. m. 



Habitat. — California. Lorquin. 



This species closely agrees in structure with S. diffinis; the body 

 squamation is rough. The coloration of the body parts, and the nar- 

 row edging of the wings, will at once distinguish the present from our 

 common species from the Atlantic District. S. thetis is the species 

 mentioned by Dr. Boisduval under the name of " Macrcxjlossa thetis^" 

 Ann. Soc. Ent. Fr. Sieme Ser. I^ull. p. xxxii. During our recent visit, 

 Dr. Boisduval kindly conmiunicated to us a specimen of 8. thetis for 

 the purpose of publishing the species, together with other material il- 

 lustrated in the present Paper, collected in California by M. ]jor(|uin, 

 and for which we have adopted the specific names with which the spe- 

 cimens were labelled by Dr. Boisduval. 



