ICHNEUMONID FINAL INSTAR LARVAE — SHORT 415 



Tribe Xoridini 



Figure 10a 



Species of this tribe parasitize wood-boring Coleoptera. 



Xorides insularis (Cresson) and X. rileyi (Ashmead) (fig. 10a) have 

 been examined. 



In the genus Xorides the dorsal part of the epistoma is not scle- 

 rotized, but the pleurostoma, hypostoma, hypostomal spur, and 

 stipital sclerite are well sclerotized; the labial sclerite is roughly 

 triangular in shape; the maxillary and labial palps each bear two 

 sensilla, one round and one cresccntic in shape; the labral sclerite 

 in both species examined does not have the dorsal part sclerotized 

 and each lateral part consists of two sclerotic bands which join ven- 

 trally; the mandible is distinctive with a broad blade bearing two rows 

 of large teeth on the dorsal surface ; the antenna is papilliform ; the 

 spiracular atrium is oval in shape and the closing apparatus is close 

 to the atrium; small setae but no spines are present on the skin. 



Ischnoceros rusticus (Geoff roy) is figured by Berine (1941), Xori- 

 descopus sp. by Ayyar (1943), X. brachylahris (Kriechbaumer) by 

 Chrystal and Skinner (1931), Xorides praecatorius (Fabricius) by 

 Beirne (1941), and Xorides sp. by Short (1952). All specimens de- 

 scribed in the literature appear to have the labral sclerite consisting 

 only of a single sclerotic band and not double as in the species figured 

 in the present paper. Chrystal and Skinner show small lobes on the 

 ventral surface of the labial sclerite of X. brachylahris. The labium 

 thus resembles those of some Ephialtini. These authors also record 

 that there is no striking difference between the larva of this species 

 and that of X. irrigator (Fabricius) which they also examined. These 

 lobes have not been recorded on the labium of any other species of 

 this tribe, although Ayyar figures what appears to be a sclerotic plate 

 beneath the ventral surface of the labial sclerite in Xoridescopus . It 

 is unfortunate that this figure is poor and on bad paper. 



Tribe Acaenitini 



Figure 10b 



Members of this tribe are parasites of wood-boring Coleoptera. 

 The only species of this tribe examined was Arotes formosus Cresson 

 (fig. 10b). Cushman and Rohwer (1921, p. 392) state that the group 

 is ectoparasitic. The complete epistoma, toothless mandible and 

 small skin setae of Arotes suggest that it is an endoparasite, although 

 the larval characters of Coleocentrus , as figured by Baumann (1933), 

 suggest that this genus is an ectoparasite. 



