7892 



Insects. 



antennae have 18, 19 or 20 joints, the basal joints being bright yellow, 

 the others dirty yellow or brownish ; they are distinctly serrated on 

 the under side, but are not provided with the beautiful pectination of 

 the male. On the thorax are three large black or dark purple spots, 

 the first covering nearly the whole of the surface of the anterior division 

 of the mesothorax ; the two others, which are situated at the sides of 

 the thoracic surface, are elliptical and curved, having their convex 

 sides towards each other. Between these last are two smaller spots. 

 In dark-coloured individuals the black colouring is more diffused, in 

 some instances covering the whole of the middle of the thorax. The 

 scutellum is yellow, the posterior margin being generally black, which 

 sometimes extends beyond the middle. In Germany, where this spe- 

 cies is more generally met with than with us, individuals have been 

 found having the entire scutellum black. The breast is almost always 

 wholly yellow, but a few examples have been observed with a black 

 spot on the breast. The upper surface of the metathorax is almost 

 always entirely black, and very rarely having yellow spots on the sides. 

 The abdomen varies much in colour, in the extent of the black marking, 

 which forms a shining spot in the centre. The first segment is yellow, 

 with or without a very small central triangular spot; the second is either 

 yellow, with a similar little triangular spot, or black with yellow mar- 

 gins; the four following are almost always black in the centre and 

 yellow at the sides, the yellow being divided from the black by diver- 

 ging notched lines. The seventh segment has generally a small tri- 

 angular mark in the centre ; the remaining segments are yellow, which 

 colour is also that of the under side of the abdomen and of the legs, 

 with the exception of some small spots on the coxae and femora. It 

 only remains to add that the extremities of the tibiae and of the joints 

 of the tarsi are darker than the ground colour, and that the wings are 

 hyaline, but reddish towards the apex. (See fig. 6). Hartig records 

 as a distinguishing characteristic of this species that the extremities 

 of the under wings are blackish ; I do not find this to be the rule with 

 specimens taken in this country; on the contrary, it seldom occurs 

 here. 



Both King and Hartig have given themselves the trouble of describing 

 all the varieties in coloration which they have observed in the female 

 of this species, to the number of fourteen or fifteen. We shall, however, 

 not follow them in this. 



The saw of the female consists, as in the other tree-wasps, of two 

 equal parts, which, when applied to each other, are pointed and more 

 or less curved. They have nine oblique rows of teeth, and on the 



