1910.] FOSSORIAL WASPS OF AUSTRALIA. 291 



Ventral surface more closely and coarsely punctured, the fifth 

 segment coarsely longitudinally striated. Pygidium long and very 

 narrow, linear at the base ; sharply deflexed posteriorly and very 

 narrowly elongate-ovate, with a short but strong longitudinal 

 carina at the base. Basal joint of intermediate tarsi normal. 



Ferruginous brown ; the apex of the mandibles, median seg- 

 ment, the apical half of the third dorsal abdominal segment, and 

 the whole of the fourth, fifth, and sixth segments black. 



Length 13 mm. 



Hob. South Perth, W. A. (H. M. Giles). s 2 in cop. 



" On Leptospermum bloom." 



A male of this species was sent by Mr. Giles paired with a 

 female of G. assimilis Sm. taken on Eucalyptus Jicifolia. He 

 states that cross-pairing is occasionally met with in the Thynnidae. 



Lestricothynnus optimus Sm. 



Thynnus optimus Sm. Oat. Hym. B. M. vii. p. 29. n. 74 

 (1859), d. 



Thynnus {Aeolothynnus) optimusTum. Proc. Linn. Soc. N.S.W. 

 xxxiii. p. 125 (1908), d. 



This should probably be placed in the section of the genus 

 near nubilipennis Sm., though differing in the more flattened 

 abdomen, the shape of the hypopygium, and in the position of the 

 second recurrent nervure, which is strongly curved and received 

 very near the base of the third cubital cell. Except in the latter 

 character it is very near L. illidgei described below. L. sulcatus 

 Sm. is most probably the female of this species, being allied to the 

 female of L. illidgei, but the very fragmentary condition of the 

 t} r pe renders close comparison in some points impossible. 



Lestricothynnus illidgei, sp. n. 



<S . Clypeus convex in the middle, produced and rather broadly 

 truncate on the apical margin, very finely and sparsely punctured, 

 with a slightly depressed mark on each side before the apex, 

 pointed at the base and connected with the interantennal 

 prominence by a short carina. ; the labrum projecting slightly 

 beyond the clypeus and broadly rounded at the apex. Palpi 

 slender, but not elongate ; the basal joint of the labial palpi about 

 as long as the second and third combined. Antenna? longer than 

 the thorax and median segment combined, the apical joints very 

 feebly arcuate and a little slenderer than the others ; the distance 

 between the antenna? at the base rather less than that between 

 the base of the antennae and the eyes. Head small, opaque and 

 closely punctured, broader than the pronotum ; the interantennal 

 prominence V-shaped. Pronotum shining and almost smooth, the 

 anterior margin very slightly raised ; mesonotum closely punctured, 

 less closely so on the disc than on the sides, with the usual two 

 longitudinal sulci on each side. Scutellum and median segment 

 shining, shallowlv and rather sparsely punctured ; the scutellum 



19* 



