202 Journal New York Entomological Society. [Vol. xxiv, 



species, these indentations being called ocellar pits. In males of 

 those species in which the compound eyes converge above, the hind 

 ocelli touch the inner margin of the eyes. The color of the ocelli is 

 darker than that of the eyes; it is sometimes black but more often 

 brown. 



Thorax. 



The thorax, as in most Hymenoptera, in addition to the three tho- 

 racic segments of other insects, includes the propodeum or first 

 abdominal segment. 



Prothorax. — The pronotum is firmly attached to the anterior mar- 

 gin of the mesonotum. Laterally it is prolonged in the form of a 

 lobe, the pronotal lobe, which extends backward nearly to the meso- 

 thoracic epimeron. There is an oblique groove extending from the 

 front of the notum to the base of the pronotal lobe, which divides 

 the former into an upper and two lower plates, one on either side of 

 the body. Between these two plates lies a pair of sclerites on the 

 ventral surface approximated along the median ventral line and 

 usually called the prosterum, though really constituting the propleu- 

 ron. In this paper the usual name, though morphologically inaccu- 

 rate, is retained for convenience. 



The lower lateral plate of the pronotum, which is usually termed 

 the propleuron, extends downward on each side from the base of the 

 pronotum and pronotal lobe and becomes greatly narrowed ventrally. 

 The pronotum is slightly concave on each side. The sternum of this 

 segment has become reduced almost to nothing, only a trace of it 

 remaining close to the fore coxae. 



Mesothorax. — The mesonotum consists of two plates, the scutum 

 and the scutellum. The scutum is the very large anterior plate which 

 extends from the posterior margin of the pronotum back to a point 

 over the middle of the hind wing. It is quite convex, especially in 

 front, where its antero-lateral angles extend downward to the pro- 

 notal lobes. Running backward from the anterior margin of the 

 scutum is a faint median suture which becomes obliterated at about 

 halfway to the posterior margin. A short distance from this line 

 and extending parallel to it are two short sutures, one on either side, 

 the parapsidal furrows. On the middle of the plate is a large, shin- 

 ing, impunctate area without pilosity, which in some species extends 

 back even to the middle of the scutellum. This is known as the disk 



