52 HYMENOPTEKA. 



is doubtful, furthermore, if the relationship between the Neotropical genera and Perga 

 is real, for the points of agreement (apart from the spined tibiae, the enlarged scapulae, 

 and an agreement in the form of the scutellum) consist in a reduction in the number 

 of joints in the antennae and palpi, and in the lanceolate cellule being obsolete; and 

 these may have become degraded independently in both countries, so that on this view 

 the resemblance in these respects cannot be looked upon as one of affinity. That the 

 number of joints in the antennae and palpi has been reduced rather than that six or 

 seven was the number with the ancestral Tenthredinidse is shown alike by the fact that 

 the Siricidae (which are certainly older than the Tenthredinidae) have multiarticulated 

 antennae, and that in badly developed specimens of Cimibex and Perga the club shows 

 two more joints than is usually present, that is to say, the joints have become amal- 

 gamated towards the apex. This view is further borne out by the antennae with few 

 joints being always clavate or semiclavate and short. The lanceolate cellule is one of 

 the characteristic features of the Tenthredinidae. In the few cases where it is absent 

 there is either an abbreviation in the joints of the antennae or palpi, or both; and, so 

 far as I know, it is only absent in genera inhabiting Australia or South America. That 

 it has become obsolete is proved by its excessive reduction in Perreyia &c. ; while the 

 accessory nervure in the hind wings is often absent in species where it is usually 

 present. 



Subtribe SYZYGONIDES. 



Labium entire. Labial palpi 3-jointed; maxillary 4-jointed. Cubital nervure issuing 

 from the transverse basal nervure. Spines and calcaria short, thick. 



The above characters sufficiently distinguish the Syzygonides from the Lobocerides. 

 At present the only genera I can refer to this subtribe are Syzygonia and Incalia. 

 Whether Cephalocera, Klug, should be referred to it or to the Lobocerides is a question 

 that can only be settled by an examination of the type. 



INCALIA. 



Incalia, Cameron, Trans. Ent. Soc. 1878, p. 143. 



This genus is exclusively Neotropical, and contains at present only one species. It 

 differs from Loboceras in having the antennae thicker throughout, in the spurs being 

 much shorter and thicker (not much more than one third of the length of the 

 metatarsus), in the hinder tibiae bearing a spine, and in the palpi having fewer joints 

 (the maxillary palpi being 4- and the labial 3-jointed), besides being short and thick. 

 The basal joint of the maxillary palpi is the shortest, being, however, not much 

 shorter than the third, which, again, is shorter than the second; the fourth is the 

 longest and thinnest. The joints of the labial palpi are subequal. The mandibles are 



