HYMENOPTERA 15 



Crauronidae. 



Crabro {Solenius). 



The fifteen species which I have referred to the sub-genus Solenms of Crabro 

 fall naturally into three groups, which are readily distinguished by structural characters 

 in the (f, but the females present no special distinctions in the two groups, in which 

 this sex is known. In the first group the sixth joint of the i antennae is produced 

 into a rather long prominent tooth at its apex ; in the second it is emarginate, but only 

 slightly produced. The third group contains only two species (one of which I have 

 never seen), the </ only being known, remarkable for the form of the ventral abdominal 

 segments. Possibly, however, Blackburn's C. abnormis does not really belong to this 

 group, and C. curtipes is the only representative. Although I have referred these 

 Hawaiian species to the sub-genus Solenms, I have no doubt they will ultimately form 

 one or more peculiar genera. The pygidial area of the ? is flatter, less elongate 

 and excavated than in typical Solenms, and there are other differences. The punctu- 

 ration is very similar in most of the species, and is generally feeble and shallow, often 

 subobsolete. The chief characters for specific distinction are found in the antennae 

 of the (/■, differences in sculpture of the thorax, the colour of the pilosity of the clypeus, 

 of the antennae, mandibles, &c., and in the form and sculpture of the second ventral 

 segment of the abdomen. 



(i) Crabro {Solenuis) monticola, sp. nov. 



Niger, clypeo argenteo-piloso, abdomine flavo-notato, alis subhyalinis. cf an- 

 tennarum articulo sexto fortiter dentato. <^i. Long. 5-5 — 9-5 mm. (Plate I. figs. 6 

 and 6 a.) 



Male black, second segment of the abdomen with a yellowish-white fascia at the 

 base, sometimes reduced to a round spot on either side. Third segment black, or 

 with a spot on each side ; fourth sometimes with an entire fascia, more often an 

 interrupted one, sometimes only a spot on each side, or entirely black ; fifth with 

 an entire fascia, often very broad, as also the sixth segment. Head and mandibles 

 black, the clypeus with appressed silvery pubescence ; antennae with the fifth joint of 

 the flagellum emarginate beneath and strongly produced at the apex into a projecting 

 tooth ; vertex dull, the surface rugulose with very shallow and obscure subobsolete 

 puncturation. Mesothorax dull, clothed with thin pale pubescence, the surface 

 densely rugulose, with very feebly impressed punctures. Propodeum longitudinally 

 rugose in front, the surface dull, clothed with pale hairs. Abdomen subovate shining, 

 with very fine indistinct punctures ; second ventral segment very finely, but not 

 closely punctured, except on a round area on either side, where the punctures are 



