HYMENOPTERA 



969 



to some shrub or tree. I find no other account of the habits of this 

 species, and the other species of Zethus the habits of which have been 

 described build nests of a very different type. Saussure ('75) states 

 that Zethiis romandiniis, found in Cayenne, "constructs with woody 

 fibres and gummy materials several rounded cells, with thick walls 

 toward the bottom and irregularly united, recalling a little those of 

 Bombtts." Ducke ('14) describes and figures the nest of a Brazilian 

 species, Zethus lohuldtiis. This nest consists of a long mass of cells, 

 suspended from a twig and is composed of fragments of leaves cement- 





Fig. 1184. — Nests of Pesudomasaris vespoides: a, incomplete nest; b, diagram of a 

 cell showing the cup at the upper end; c, completed nest. 



ed together by a resinous substance. Williams ('19) describes the 

 nest of Zethus cyanopterus, which he observed in the Philippines; this 

 nest is made of bits of leaves which "are chewed along one or more 

 of their edges which makes them adhere the more firmly to the nest." 

 This author says nothing about the use of a gummy material for 

 cementing together the fragments of leaves. 



Subfamily EUMENIN^ 

 The Eumemds 



This subfamily includes b}^ far the greater number of our species 

 of the solitary Diploptera ; and is represented in our fauna by about 

 eight genera. The distinguishing features of these wasps are indicated 

 in the table of subfamilies given above. 



