ICHNEUMONID FINAL INSTAR LARVAE — SHORT 427 



sclerite is roughly triangular in shape in most genera, but, as stated 

 below, this sclerite may be circular or otherwise modified; the silk 

 press is well sclerotized and conspicuous and two small sensilla are 

 often visible just beneath the external opening of the press; each 

 maxQlary and labial palp usually bears two sensilla, one round and 

 one crescentic in shape, although three or more sensilla are present 

 in some genera; the labral sclerite is usually lightly sclerotized in its 

 dorsal part and this part may be enlarged; the mandibles are rela- 

 tively small in most genera, except in the Aptesini where they are 

 of moderate size; teeth may be present on the dorsal and ventral 

 surfaces of the blade of the mandible, on the dorsal surface only, or 

 teeth may be absent; the antenna is usually papilliform, although 

 it is disc-shaped in some Hemitelini; the closing apparatus of the 

 spiracle may be some distance from the atrium or it may be close to 

 the atrium; the skin bears setae and small projections which may be 

 sufficiently sclerotized to appear as spines. 



Larval Key 



1. Hypostoma posterior to hypostoinal spur shorter tliau hypostomal spur. 



Bracliy cyrtini 

 Hypostoma posterior to hypostomal spur at least as long as hypostomal spur . . 2 



2. Mandible with a long slender blade bearing a row of fine teeth along entire 



length of dorsal surface Sphecophagini 



Mandible not of this form 3 



3. Teeth on dorsal surface of blade of mandible larger than teeth on ventral 



surface '^ which are very small and few in number, except in Rhernhohius 

 (fig. 21a) where the blade of the mandible is short, broad and well sclerotized 

 with length equal to one third of that of base of mandible and width of 



lateral end equal to one third of width of base Aptesini 



If teeth present on dorsal and ventral surfaces of blade of mandible and teeth 

 on dorsal surface markedly larger than teeth of ventral surface, then ventral 

 teeth numerous ^^ and blade of mandible longer and more slender than in 

 Rhernhohius, with length greater than one third of that of base of mandible 

 and with width of lateral end less than one third of that of base 4 



4. Closing apparatus of spiracle separated from atrium by length of trachea at 



least equal to length of closing apparatus, or, if not, then epistoma not 



sclerotized dorsal to anterior tentorial pits Hemitelini 



Closing apparatus of spiracle adjoining atrium, or if not, then at least part 

 of epistoma dorsal to anterior tentorial pits lightly sclerotized '* . . Cryptini 



'2 Except Cubocephalus where the form and position of the closing apparatus of the spiracle diflerentiates 

 this genus from Cryptini with a similar type of mandible and either the form of the labial sclerite or the 

 form and position of the closing apparatus of the spiracle differentiates this genus from Hemitelini with 

 a similar type of mandible. 



>' Except Trychosis, Mallochia and Lymeon (Cryptini). The following characters will distinguish these 

 genera from the Aptesini: the form of the labial sclerite in Trychosis, the sharp dorsal bend of the lateral end 

 of the stipital sclerite in Mallochia, and the heart-shaped dorsal senslllum on each labial palp in Lymeon. 



'« Except Pseudischnus. 



