116 



Caput et antcnn.TB Lydne, abdomen MiitilloB. Alarum ncni ut in Myr- 

 mosa disposili."* He here, however, assigns no situation to it ; and 

 in 1840, in his 'Introduction to the Modern Classification of Insects,' 

 he says, towards the end of his remarks on the Mutillida3,t " I may 

 here mention another anomalous genus, which I have described under 

 the name of Trigonalys, having somewhat of the aspect of a male 

 Mutilla, but with the head flattened and the antennae longer, very 

 slender at the tips, and composed of twenty-three or twenty-four joints, 

 very like those of Lyda ; the legs are simple, and the abdomen punc- 

 tured. The veins of the wings are nearly as in Myrmosa and Mutilla 

 Europa3a, mas. The type, T. melanoleuca, is from the Brazils." 



Mr. Westwood should not have been long in doubt as to the afii- 

 nities of the genus in question, as the antennae, in the first place, ought 

 to have told him that its position could not be near Mutilla and Myr- 

 mosa, for although the aculeated Hymenoptera have sometimes appa- 

 rently fewer than the normal number of joints, that is, twelve in the 

 female and thirteen in the male, no instance is yet known, I believe, of 

 their exceeding that number. Presenting thus, therefore, at once, this 

 almost insuperable objection to the situation he assigned it, he might 

 have looked further into its structure, and he would then have found 

 that the trochanters are two-jointed, — a peculiarity not yet known 

 to occur in the aculeated Hymenoptera, and presenting itself exclu- 

 sively in Latreille's Pupivora. And here, a moment's reflection would 

 have told him sufficiently, that the only genus yet described in this 

 division with two recurrent nervures and a closed first submarginal 

 cell, is Aulacus ; and having arrived here, other very proximate affi- 

 nities must have immediately exhibited themselves, namely, in the 

 form of the head, and its attachment by a neck to the prothorax, the 

 insertion of the antennae, and the structure of the mandibles and pal- 

 pi. All this is still further confirmed by the insertion of the abdomen 

 in the new genus I shall describe below, which, although not placed 

 upon so long a projection of the metathorax as in Aulacus, the projec- 

 tion is still longer than the posterior coxae. I therefore, without any 

 hesitation, place it next to it, and conjunctively form of them a fa- 

 mily, the designation of which I derive fi-om the genus first described, 

 although perhaps it is not normally its type ; this however is in strict 

 adherance to the law of priority. That Aulacus should be removed 

 from the Evaniadae, there can be no doubt ; for the insertion of the 



* Proceedings of the Zoological Society. April, 14, 1835, No. 28, p. 53. 

 t Introd. to Mod. Class. Vol. ii. p. 215. 



