1902.] SPIDERS FROM BORNEO AND SINGAPORE. 261 



enjoys is doubtless due to the closeness of its resemblance to an 

 equally conspicuous Scdius, an ally of which has already been 

 noted as the model of a Longicorn beetle. The fore wing of the 

 Laphria is large, almost as broad as both fore and hind wing 

 together of the Salius and of the same clear golden-brown. The 

 thorax, as in the wasp, is covered dorsally with a golden pubes- 

 cence, whilst the abdomen, like that of the model, is black, and 

 terminates in a sharp tufted point very suggestive of a sting. 

 All the tibife and tarsi are ochreous, but the black and thickened 

 femora are very unlike those of the Salius. No attempt at 

 mimicking the long ochreous antennee of the wasp is made, as in 

 some other Diptera shortly to be described (compare figs. 9 & 10, 

 Plate XXII.). The buzzing, noisy flight of this fly is very like 

 that of its model. 



[In the natural attitude of rest it is probable that the black 

 femora of the fly are held upright and near to the body, so that 

 the ochreous parts of the legs would alone be conspicuous. It is 

 noteworthy that the under sides of the anterior femora are 

 ochreous, suggesting that the anterior limbs may in certain 

 attitudes be raised, or, at any rate, that they are held so that this 

 part is more conspicuous than any othei- femoral surface. It is 

 probable that this special colouring is directed to meet a view 

 from the front. It is to be hoped that future observations will 

 be specially directed to these points. This fly belongs to the 

 family of the Asilida? (subfamily Laphrhue), the most formidable 

 and predaceous of Diptera, and it is quite possible that the 

 resemblance to a wasp is Miillerian (synaposematic) rather than 

 Batesian (pseudaposematic). — E. B. P.] 



ii. Mimic. Hyperechia fera (v. d. Wulp). Plate XXII. fig. 2. 



Model. Xylocojja latipes {Tivnij). Plate XXII. fig. 1. 



No more remarkable proof of the plasticity of the Dipterous 

 form could be advanced than this remarkable insect. The large, 

 clumsy Xylocopa, with its bronzy wings and thick furry legs, 

 would seem to be an eminently unsuitable and difficult model to 

 copy ; and it would be most instructive, if only it were possible, to 

 trace the steps by which this fly has arrived at what at first sight 

 appears to be the pitch of mimetic perfection. As a matter of 

 fact the fly is extremely rare, and one can only conclude that the 

 mimicry, exact though it seems, has failed to preserve the species 

 as a dominant one. 



The head is characteristically Dipterous; the thorax is of 

 shining blue-black, clothed with a fine dense pubescence, coarser 

 and longer on the sides ; the broad, flattened abdomen is laterally 

 bordered with a fringe of long hairs exactly as is the case with 

 the Xylocopa, and terminates in a fine tufted process suggestnig 

 a sting. As in X. latipes, all the legs are remarkably hairy and 

 sturdy, particularly the last pair, and are of much the same 

 lenc^th. The wings are of a bluish-bronze hue : the downwardly- 



