344 EDWARD NORTON. 



3. C. mexicanus. 



Cephus viexicanus, Guer. Icon. Reg. Anim,iii, 403. 



" Black; mandibles having a large longitudinal yellow spot in niiil- 

 dle of their leugth; two very small yellow spots in the middle of their 

 front, below the antennas; more spots of the same color on the border 

 of the eyes near their superior border and on the sides of the head, 

 behind the eyes. There are two yellow spots upon the scutellum ; the 

 exterior side of the posterior haunches is yellow, and the knees and 

 the tarsi are of a yellowish brown. Wings transparent, lightly smoky 

 toward the extremity and the nervures brown. Abdomen black, with 

 the second, third, and fifth segments largely bordered with yellow 

 above; this band indented anteriorly and interrupted in the middle 

 (female). Long. 15. Br. wings 22 mill. 



" Mexico. 



" This species is of the size of C. laii/ras, and resembles it very 

 much." 



fil. JANUS, Steph. 

 Janus, Stephens, Brit. Ent. Mand. vii. 1835, 107. 

 Cephas, Curtis. 



Wings &s in Gephus; areolets of different shape. AnieJtnm multi- 

 articulate, filiform. Abdomen short, narrow at the base and dilated 

 at the tip, which is obtuse and rounded in the males, slightly com- 

 pressed and acute in the females. 



Stephens founds the diflerence between this and C'ephua, on the long 

 filiform antennre, the difference in the structure of trophi, and in the 

 areolets of wings and the abbreviated subclavate abdomen. 



I. J. flaviventris. 



Janus fiaviventris, Fitch, 7th Rep. Nox. Ins. No. 12. 



''Shining black, hind body yellow except at its base, its mouth be- 

 ing straw colored and also the hind margin of its collar, the base of its 

 wings, a small spot above their sockets and the fore and hind margins 

 of the metathorax. The hind body is narrower than the fore body and 

 more narrow and long than in the typical species of this genus, forming 

 almost two-thirds of the length of the insect. Its basal segment is 

 black, edged anteriorly with straw yellow and with a slender line of 

 this color along its middle, ending in a large triangular spot. The 

 second segment is also black at its hinder end and on the sides is a 

 blackish cloud on the sutures of each of the remaining segments. 

 The wings are hyaline and glassy, their stigma sooty brown, which 

 color extends inward occupying most of the anterior marginal cell. A 

 faint smoky cloud may also be perceived near the middle of the poste- 



