274 Mr. F. Walker's Characters of undescribcd DipLera 



callus, in front of which there is a black shining quadrate spot; 

 underside whitish, with white hairs; palpi whitish; antennae 

 tawny, dilated into a tooth at the base of the third joint, black 

 towards the tips ; thorax with cinereous tomentum ; pectus whitish, 

 with white liairs ; abdomen with three testaceous stripes ; the 

 lateral stripes composed of oVjlique elongated testaceous spots; 

 underside pale testaceous; legs testaceous; tarsi, femora at the 

 bnse, and tibi.'je at the tips, black ; fore legs deep black, their 

 tibiae testaceous for half the length from the base; wings grey; 

 veins black, ferruginous at the base ; transverse veins hardly 

 clouded ; fore branch of the cubital vein obtusely angular at the 

 base, not emitting a branch ; sub-anal vein joining the anal at 

 some distance from the border ; halteres white. 



Length of the body 5| lines; of the wings 10 lines. 



Mexico. 



Tahanus aUeripenn'is, 



Teem. — Ferrugineus, capite albido, callo gracillimo, antennis 

 luteis, dente apiceque nigris, thorace vittis tribus obscuri- 

 oribus, pectore cano, abdomine apicem versus nigricante, 

 pedibus anticis nigris, alis oliscure cinereis albo-trimaculatis, 

 stigmate nigricante, halteribus albidis apice nigris. 



Allied to T. diver SI penn'is. Female. — Ferruginous : head with 

 whitish tomentum; callus very slender; eyes nearly contiguous 

 above; proboscis blaclv ; antennae Inteous, black towards the tips; 

 tliird joint slightly dilated, and with a minute black tooth near its 

 base; thorax with three indistinct darker stripes; pectus hoary; 

 abdomen blackish above towards the tip, with the exception of 

 the hind borders of the segments ; fore legs black ; wings dark 

 grey, with three white spots on the disk of each, the third spot 

 smaller than the other two, and on the base of the fore branch of 

 the cubital vein, which has the usual form, and emits no fork ; 

 stigma blackish ; halteres whitish, with black knobs. 



Var. B. Darker : abdomen not blackish towards the tip ; wings 

 partly blackish. 



Length of the body 4g lines; of the wings 10 lines. 



Mexico. 



Tabanus pio-us. 



Fcem. — Pallide testaceo-flavus, callo longo gracili antice sub- 

 dilatato, proboscide nigro, thorace pectoreque albido-sub- 

 tomentosis, alls limpidissimis, venis albido-testaceis, venae 



