NO. I BLACK FLIES OF GUATEMALA — DALMAT 213 



striations. Submentum with 9 apical teeth, triangular in shape, the 

 central tooth and the outermost tooth on either side longer than the 

 others ; ventrolateral row composed of 4 to 5 hairs, usually simple ; 

 when there are five hairs in the row, the two basal hairs are usually not 

 in line with the other three ; lateral margin of submentum with 7 tooth- 

 like structures, the two most-distal teeth well sclerotized, situated just 

 lateral to the outermost of the apical teeth, the others more basal. 

 Occipital cleft narrow, small, the margin irregular (pi. 43, fig. 416). 



Thorax and Abdomen : Pseudopod (thoracic proleg) with 34-38 

 rows of spines at its apex; postclypeal sclerites so small that they 

 usually are not visible. Posterior sucker with 68-76 rows of hooks. 

 Anal gills composed of 3 main divisions, each of which usually is 

 simple; at times, each division has two further branches. Anterior 

 and posterior arms of X-shaped sclerite heavily sclerotized, without 

 expansions or patches ; posterior arms are at right angles to the long 

 axis of the larva, completely encircling the posterior sucker ; less 

 heavily sclerotized on ventral surface ; no rectal scales. Two pro- 

 nounced ventral papillae on eighth segment, conical, well pigmented ; 

 no sclerotized plaques. 



Types.— (^' (U.S.N.M. No. 28348), collection of the United States 

 National Museum ; collected at Jacumba Springs, Calif., U. S. A. 



SIMTJLIUM (SIMULIUM) JOBBINSI Vargas, Martinez, and Diaz 



Sitmilium (Simidium) jobbinsi Vargas, Martinez, and Diaz, Rev. Inst. Salubr. 

 Enferm. Trop., vol. 7, No. 3, pp. 147-I4g, figs. 87-90, 1946 (original descrip- 

 tion, (S, 5, and pupa). — Dalmat, Ann. Ent. Soc. Amer., vol. 44, No. i, pp. 

 54-57. 1951 (presence and distribution in Guatemala). 



Male (pi. 25, figs. 76-78). — 3.0 mm. long. 



Head: Holoptic. Eyes reddish brown. Antenna 560 ju, long, 11- 

 segmented, slightly tapering; segment 3 = 1-1-2, 3<4-|-5, 3>li; 

 black. Palpi black. Clypeus black, partially white-pruinose, with 

 single row of long black hairs along lateral and distal margins. 



Thorax : Mesonotum dark reddish brown, velvety ; band of white 

 pruinosity around entire periphery, broader along posterior margin ; 

 band interrupted at middle of anterior margin where there is either a 

 diffusion of the color or where 2 medially directed arms are formed, 

 the arms directed somewhat toward the center of the scutum ; long, 

 narrow, brown, appressed hairs on anterior fourth of mesonotum, long 

 black ones in prescutellar region and a few on anterior margin. Hu- 

 meral angles brown to black, with white pruinosity. Scutellum shiny 

 dark brown, with long, strong, black hairs. Postnotum velvety dark 

 brown, white-pruinose, devoid of hairs. Pleura dark brown, with 



