GENUS POBOILOSOMA. 207 



cubital nervure is usually absent, either constantly in 

 particular species, or occasionally with certain species. 

 In the same way the hind wings may want the recur- 

 rent nervure, and when this is combined with the 

 absence of the first transverse cubital nervure in the 

 front wings, we get the neuration of Emphytus. The 

 relative size of the third cubital cellule varies in the 

 different species, as does also the position of the 

 recurrent nervures. 



The larvaB are similar to those of Tavonus, and have 

 the same habits. Nine European species are known 

 and two North American. 



s of Species. 



1 (2) Abdomen luteous. Antenna} short, thick, the joints sharply cut 



off from each other and slightly produced at the apices 

 beneath. Wings with four cubital cellules, hind wings with 

 the recurrent nervure present. Head distinctly inflated 

 behind the eyes. Clypeus deeply incised. Antenna! fovea 

 large (=Monostegia > Costa). Luteolum. 



2 (1) Abdomen black. 



3 (8) Legs for the greater part white or luteous, the abdominal seg- 



ments broadly bordered with white. 



4 (5) Hind wings with the recurrent nervure absent. Antennas not 



much longer than double the length of the head, third joint 

 not much longer than fourth. Face and orbits of eyes white. 

 Clypeus broadly, but not deeply emarginated, Claws with a 

 minute subapical tooth. Candidatum. 



5 (4) Hind wings with the recurrent nervure present. Antennae dis- 



tinctly longer than head and thorax. 



6 (7) Legs entirely luteous, first transverse cubital nervure present. 



Antennae short, the third joint much longer than fourth ; 

 third cubital cellule long and narrow. Pulveratum. 



7 (6) Femora lined with black, first transverse cubital nervure absent. 



Antennas longish, attenuated at the apex ; third (second) 

 cubital cellule short and broad. Fletcheri. 



8 (3) Abdomen and legs black ; pronotum with a white line ; abdomen 



often bearing white lateral spots. Recurrent nervure in 

 hind wings present ; first cubital nervure often absent 

 (=guttatum, Fall, and impressum, Kl.). 



9 (16) Pronotum lined with white. 



10 (11) Hinder calcaria a third of the length of metatarsus, antenna; 



thickish, wings infuscated, claws bifid. Guttatum. 



11 (10) Hinder calcaria not a third of the length of metatarsus ; antenna? 



attenuated at the apex ; wings subhyaline. 



12 (15) Posterior tibiae and tarsi not broadly white at base ; costa and 



stigma black, clypeus truncated at apex. 



