502 PROCEEDENGS OF THE NATIONAL MUSEUM vol. no 



Anomalon, and the blade of eacli mandible is well sclerotized; the 

 antenna is disc-shaped ; the closing apparatus of the spiracle is lightly 

 sclerotized and adjoins the atrium; the skin has small projections 

 and small setae. 



The larval characters of the Anomalinae are strikingly like those 

 of the Metopiinae. The larvae of the two subfamilies may be distin- 

 guished by the presence of setae on the prelabium of the Metopiinae 

 and the absence of these setae in the Anomalinae except Anomalon, 

 a genus having so many special features as to be readily recognizable. 



The reduction of the labial sclerite and hypostomal spur in the 

 Anomalinae, Metopiinae, and Ichneumonmae might be correlated 

 with the relatively slight cocoon spun by these endoparasites. In 

 the head of the final instar larva of Xorides muscles are present which 

 insert on the labial sclerite (Short, 1952, p. 41, fig. 8a). The con- 

 traction of these muscles tilts forward the dorsal end of the pre- 

 labium with the opening of the silk glands. In this action the labial 

 sclerite rotates on the extremities of the stipital sclerites. The 

 labial sclerite is thus held so that movement can take place in only 

 one plane. The spurs of the hypostomae, which articulate with the 

 stipital sclerites, hold the maxillae rigid. The spinning of the cocoon 

 has been observed in Xorides and the region of the prelabium contain- 

 ing the opening of the silk glands was tilted forward during this 

 process. It is therefore possible that the reduction of a cocoon is 

 accompanied by a reduction of the muscles which evert the dorsal 

 end of the prelabium and a reduction of the labial sclerite and h3rpos- 

 tomal spur. One objection to this suggestion is that the Pimplini, 

 which emerge from the pupa of a lepidopterous host and have only 

 a slight cocoon, have a well developed hypostomal spur and labial 

 sclerite. However the stipital sclerite is reduced and this might 

 be associated with the reduction of the cocoon since, when being 

 everted, the labial sclerite rotates on the stipital sclerite. 



Larval Key 



1. Blade of mandible with teeth; setae on prelabium Anomalini 



Blade of mandible without teeth; setae absent from prelabium .... 2 



2. Width of epistoma along entire length and width of pleurostoma along entire 



length equal to at least half length of mandible Therionini 



Width of epistoma or part of width of pleurostoma less than length of man- 

 dible Gravenhorstiini 



Ophionellini ^' 

 Tribe Anomalini 



Figure 60c 



The general form of the head sclerites, spiracles, and sldn places 

 Anomalon with the genera of the tribes Gravenhorstiini and Therionini; 



» Of Cushman (1947). 



