90 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



the use of stable body characters. It is also possible that unusual 

 habits may be the cause for the development of unusual char- 

 acters which may be very valuable taxonomically, but may not 

 necessarily express the true relationships. 



In raising the oryssoids to subordinal rank we have only ex- 

 pressed in a taxonomic way the unusual, valuable, and striking 

 differences which exist between them and the Chalastogastra 

 and we believe that the parasitic habit of the larva indicates that 

 these characters are of subordinal value. 



As early as 1829 Macleay suggested that the sawflies could 

 constitute a separate order and proposed the name Bomboptera 

 and now in 1916 Crampton (Ent. News, vol. 27, p. 303) without 

 definitely limiting or giving any defining characters and for ap- 

 parently no other than theoretical reasons says: "The Hymenop- 

 terous insects should be divided into two orders, the Prohymen- 

 optera or Tenthrenid group, and the Hymenoptera proper." We 

 can see no real advantage in dividing the order Hymenoptera, as 

 usually defined, into two orders and we believe that the group, 

 as usually treated, is a homogeneous unit for which ordinal divi- 

 sion is unnecessary and undesirable. The subordinal group 

 Idiogastra is in itself sufficient reason to discard the ordinal 

 names Bomboptera and Prohymenoptera. 



LARVA OF Oryssus occidentalis. 

 (Description drawn from alcoholic specimens.) 



The larva is white, subcylindrical, about one-third as thick as long, 

 tapering slightly at each end, and somewhat flattened dorso-ventrally. 

 The caudal extremity is slightly upcurved. The constriction between the 

 head and thorax is rather weak. The head is very short antero-posteriorly 

 and less than half as broad as the greatest diameter of the body. The 

 antennae are tubercle-like and set at the summits of rounded elevations. 

 The mouth-parts are very simple, the labrum, labium, and maxillae being 

 merely fleshy lobes, the last not divided into the usual parts. On each 

 side of the middle of the labrum and near the apex is an irregular group 

 of minute sensory papillae. The labial and maxillary palpi are apparently 

 not at all developed, but on the surface of the labium are a few short, 

 stout setae and on the maxillae in a brownish area a few sensory papillae. 

 The mandibles are heavily chitinized, curved, narrow, and tridentate at 

 apex, the outside teeth equal and shorter than the median, broad at base 

 and articulating internally with heavily chitinized points at the dorsal 

 and ventral angles. The ventral articulation extends, weakly chitinized, 

 along the suture between the epicranium and the soft ventral surface of 

 the head. There is also a weakly chitinized ridge internally along the 

 lower edge of the maxilla. On plate XII, figure 1, these chitinized ridges 

 and the concealed portions of the mandibles are indicated by stippling. 



