CLASSIFICATION OF THE ASCALAPU1D.E. 



220 



family, believing, nevertheless, that the discovery of the earlier 

 stages will reinstate it in its original position *. 



Specific Characters. 

 The ordinary minor differences in form, and the colours of the 

 various members, should be taken into consideration. As this is 

 not intended as a monograph of species, I shall say little on this 

 subject, save to enjoin caution. I have already remarked that 

 the species appear to vary much according to locality in some 

 cases. How far this variation may entitle the forms to specific 

 right, or only to the minor position of " varieties," cannot be 

 considered with the materials at present in hand. Another very 

 important matter is the coloration of the wings. In many spe- 

 cies in which the wings are tinted, it is certain that the full 

 amount of coloration is not acquired until after a considerable 

 time, as in many Libellulidce. These insects are probably com- 

 paratively long-lived, and the tinting would seem to be the result 

 of a kind of oxidation of the membrane of the wing, that pro- 

 ceeds gradually. Very great caution should be exercised in con- 

 sidering the comparative robustness or obesity of the $ abdomen. 

 It is probable that many females live, for the enjoyment of life, for 

 some little time after the ova are deposited ; and in these " spent " 



* [Since these remarks were written, I have discovered a character which tends 

 to prove that Stilbopteryx has really more relationship to the Myrmelionida 

 than to the Ascalaphidce. At the extreme base of the inner margin of the pos- 

 terior wings of the male is a corneous semipedunculate knob. This is present 

 in the males of Palpares f Acanthaclisis, &c, but, I think, is always absent in 

 Ascalaphidce J\ 



I am not prepared to say how many species of Stilbopteryx may exist. All 

 that I have seen seem to pertain to the same species, differing in the spotting 

 of the sides of the abdomen according to sex. All these I refer to costalis, in 

 the <J of which the abdomen is somewhat geniculate at the fourth segment, and 

 on the dorsum of this segment there is a protuberance covered with short 

 black spines. Dr. Hagen, however (in litt.), believes he has four species. One 

 of these, from Western Australia, is very extraordinary, and has (I presume in 

 the $ only) an enormous protuberance on the base of the dorsum of the ab- 

 domen, having some analogy to the formation seen in Acmonotus incusifer, 

 which latter certainly is of the Ascalaphidce. The " nov. sp. Coll. M'Lachlan," 

 mentioned by Hagen in Stett. Zeit. 1866, p. 460, and stated on the authority 

 of a verbal communication from me to him, some years since, as coming 

 from Java, is probably only costalis. I captured it myself, in 1855, on board 

 ship. I can find no note in my journal concerning it, and now think that it 

 must have flown on board off the coast of New South Wales, and not when near 

 the island of Java, as I formerly supposed. 



