90 THE GEOUP OF HISTEIO. 



but it wants the strongly punctured thorax, while the 

 antennae are longer, thinner, and brownish on the 

 underside. 



30. NEMATUS PLACIDUS. 

 PI. XIX, fig. 5, Saw. 



Nematus placidus, Cam., E. M. M., xiv, 225 ; Andre, Species, 



i, 147 ; Cat., 19,* 107. 



Antennae nearly as long as the body, thin, filiform, the third joint a 

 very little longer than the fourth, the rest a little shorter; black- 

 brown from the second joint on the under surface. Head narrower 

 than the mesothorax, black, the labrum and palpi white; clypeus 

 almost truncated, piceous at the apex ; vertex punctured, the penta- 

 gonal area and sutures indistinct; antennal fovea large. Thorax 

 black, semi-shining, the mesonotum with a few punctures ; tegulae and 

 pronotum (largely) white; pleurae for the greater part brownish, 

 shining. Wings clear hyaline, costa and stigma white ; the first 

 transverse cubital nervure is distinct, the third cubital cellule is a 

 little longer than broad ; the second recurrent nervure is received 

 considerably in front of the second transverse cubital ; there is a small 

 horny point in the second cellule. Legs clear white, the apex of 

 posterior tibiae and tarsi (except at the extreme base) fuscous. Abdo- 

 men as long as the head and thorax, thickish, bluntly rounded at the 

 apex; black, the anal segment pale brownish- white above; cerci pale, 

 long, pointing downwards. The saw does not project. 



Length 2 lines. 



The antennas are somewhat stouter than in N. 

 arcticus, from which it is distinguished by the white, 

 not yellow, colour of the pronotum and legs. 



Rare. England (Eev. T. A. Marshall). 



X. THE GROUP OF HISTEIO. 



Ground colour obscure yellow, or fulvous. Thorax 

 and abdomen more or less marked with black, mouth 

 white, clypeus narrowly incised. Antennae not much 

 more than half the length of the body, the joints cylin- 

 drical, entirely black. Mesopleurce finely punctured, 

 pubescent, as is also the breast. Stigma pallid or livid 

 fuscous. 



