234 



MR. B. M £ LACHLAN 01S t A SYSTEMATIC 



is a very natural one, notwithstanding its variability of character 

 in the wing-formation. The position of the wings in repose 

 is unique in the family, as is also the singular formation of the 

 prothorax in the 3 . Much of this confusion is owing to Bambur 

 and others having wrongly understood Burmeister's species, and 

 confounded one of them with the Ascalaplius appendiculatus of 

 Fabricius. The genus Byas of Bambur is certainly identical 

 with Haploghnius, as is also Amcea of Lefebvre. 



Species. 



The species are without doubt numerous, but their differen- 

 tiation is very difficult, owing to insufficient materials. The best 

 characters exist in the comparative lengths of the antennae, and 

 in the formation of the wings, especially with regard to the 

 shape of the basal portion of the inner margin of the posterior 

 pair. The smaller species (arenosus and allies) are compara- 

 tively much more robust than the larger ; and in them the pro- 

 thoracic valve of the <5 is less developed, and the hind wings, from 

 the point of termination of the cubiti in the inner margin, become 

 suddenly greatly dilated ; and in these the club of the antennae 

 is less elongate. The males appear to be less numerous than 

 the females, judging from the collective series of examples that 

 have examined. 



I. H. costatus, Burmeister. (Ascal. costatus, Burm. Handb. ii. 

 p. 1000.— A. luteus, Walk. Cat. Brit. Mus. Neurop. p. 450.— A. cir- 

 cumflexus, Walk. op. cit. p. 451. — A. contrarius, Walk. op. cit. 

 p. 452.) Antennae alarum dimidio multo longiores, rufae, vel rufo- 

 fuscae ; clava infuscata. Frons vertexque fusco-villosi. Thorax gri- 

 seo-fuscus, infra utrinque flavo bistrigatus; S prothoracis valvula 

 paullo elevata, saturate fusca, margine libero fere semicirculari an- 

 guste albo. Pedes flavidi ; tarsis nigricantibus ; femoribus tibiisque 

 anticis intermediisque supra fuscescentibus. Abdomen griseo-fuscum ; 

 in <S appendicibus parvis ante apicem instructum. Alae sat latae, 

 ad apicem acutae, vix falcatae, vitreae, vel interdum testaceo paullo 

 tinctae ; ad apicem (in £ ) plerumque late testaceae ; area subcostali 

 et interdum (praecipue in $ ) area costali infuscatis ; pterostigmate 

 albido vel flavo-albido, pallide venato ; venis venulisque nigris ; mar- 

 gine interiore anticarum ante basin leviter exciso angulo axillari 

 paullo producto. Long. corp. 15-20"' ; exp. alar. 42-50"' ; postic. 

 36-43"'. 



Apparently very common in the Amazon region, and widely 

 spread in Brazil. I have it from localities as widely separated as 



