BITING MIDGES — WIRTH AND BLANTON 461 



what indented mesad, the apicolateral processes moderately well 

 developed, bluntly triangular. Basistyle with ventral root foot- 

 shaped, the posterior heel very poorly developed, dorsal root slender; 

 dististyle moderately stout distad with bluntly pointed apex. Aedea- 

 gus with basal arch low and broad, the basal arms bent in midportions, 

 slender; distal apex with relatively slender, rounded tip. Parameres 

 each with basal knob, stem slender and curved in midportion, ventral 

 lobe very long, about two times as long as its diameter, apical portion 

 of paramere very slender, tapered to simple point. 



Distribution: Brazil; Guatemala; Panama. 



Panama records: 



BocAS DEL ToRO PROVINCE: Almirante. 



Canal Zone: Fort Davis, Fort Sherman, Loma Boracho, Mojinga Swamp. 



ChiriquI Province: David. 



Dari^n Province: El Real, Punta Patino. 



Veraguas Province: Las Palmas. 



Discussion: Through the courtesy of Dr. A. da Costa Lima we 

 have been able to examine the slide on which are mounted the five 

 cotype specimens of pachymerus described by Lutz from Rio Negro, 

 Amazonas, Brazil. As previously remarked by Lutz and by Costa 

 Lima in the publications cited, the condition of the slide is very poor 

 since the liquid mounting medium has separated for the most part 

 from the specimens, leaving them wet but not immersed in the liquid. 

 The antennae and palpi are missing, as originally stated by Lutz. 

 By dark-field illumination of the wing it is possible to make out some- 

 thing of the venation and color pattern, which agree so far as can be 

 determined with that described above for the specimens from Guate- 

 mala and Panama, and are quite distinct from the characters of 

 uniradialis Wirth and Blanton and caprilesi Fox. The wing length 

 measures 0.80 mm. and the costal ratio is 0.69. We are thus able 

 to conclude with fair assurance that our species is conspecific with 

 Brazilian pachymerus. 



Culicoides pachymerus is smaller than uniradialis and caprilesi, its 

 wing is less hairy than that of caprilesi, there is no dark spot or con- 

 nection immediately posterior to the end of the second radial cell as 

 in caprilesi, and the last segment of the antenna is much longer than 

 the tenth (22:14, compared with 18:16 in caprilesi). The male geni- 

 talia of pachymerus closely resemble those of uniradialis, with a long 

 ventral lobe present on the parameres, but differing in having a 

 median notch on the ninth tergum, aedeagal arch much broader with 

 slender basal arms and no barbs on the tips of the parameres, 



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