184 SUB-TRIBE SELANDRIADES. 



or simple spines all over the body, while other larvae are covered with a 

 resinous exudation or with a white flaky substance. They either spin a 

 simple cocoon (usually with grains of earth mixed with the silk) or 

 simply bore into the stems of plants, and pupate there without the 

 protection of a cocoon. 



As above defined the Selandriades are distinguished 

 from the Tenthredinides by their much smaller size, 

 shorter spurs, and generally by the position of the 

 basal nervure. They have never a perpendicular cross 

 nervure in the lanceolate cellule, while in those species 

 which have both the recurrent and transverse cubital 

 nervure they are received close to each other, instead 

 of being wide apart as in the Tenthredinides. The 

 genera Strongylog aster and Taxonus approach very 

 close to some of the Tenthredinides, but the form of 

 the neuration and the spurs at once separate them, 

 while the smaller species differ altogether in body 

 form, in the petiolated or contracted lanceolate cellule 

 and by the absence of the transverse cubital nervure 

 in the posterior wings. It is very doubtful if the two 

 groups can be kept apart when the extra European 

 species have been examined and compared with those 

 of the European fauna. Strongylog aster, Taxonus and 

 Pcecilosoma are placed by Andre in the Tenthredinides, 

 but these genera agree with the Selandriades in the 

 short spurs and in the position of the basal nervure, 

 while the first-mentioned genus, which in its typical 

 species 8. cingulatus, comes near to the Tenthredi- 

 nides by its elongated body, is scarcely to be distin- 

 guished from the genus Selandria other than by the 

 latter having the costa somewhat dilated before the 

 stigma, and yet Selandria is placed by the French 

 author in the Selandriades. 



I once thought that the Selandriades as defined by 

 Thomson might be split up into three or four groups, 

 but I have abandoned this idea, because on a rigid 

 comparison I found it impossible to get structural 

 characters to distinguish them. For example, the 

 genera Phyllotoma, Fenusa, Fenella form an apparently 

 well-defined section, yet some of the species of Blenno- 



