OF WASHINGTON, VOLUME XIX, 1917 175 



representing four genera which were made in connection with the 

 study of the wood and pith boring Chalastogastra larvae. 



In the preparation of this paper the larvae of the genus Syntexis 1 

 were examined but they were in such poor condition that their 

 position could not be ascertained. In those characters least 

 distorted this genus approached, though did not agree with, the 

 Xiphydriidac rather than the Cephidae. 



The presence of the anal prong in the larvae of the Cephidae 

 allies them with the Siricids while the presence of palpiform ap- 

 pendages on the ventral anal lobe connects them with the Pam- 

 philids. The taxonomic position which the Cephidae should 

 occupy, will be discussed in more detail in a later paper. 



Characters common to all the genera studied and probably to 

 the family Cephidae: 



Head. Nearly round, mostly pale, mandibles and labrum darkened; 

 maxilliary palpi 4 jointed; labial palpi 3 jointed, (both palpi appearing in- 

 distinctly as if terminating in a small button); antennae 4-5 jointed; 

 mandibles 4 toothed and with a smooth, slightly curved thin blade dor- 

 sally, under the labrum, (4th or ventral tooth small and on the inner edge of 

 the mandible); frons and head generally rather sparsely spined. 



Thorax. -A pair of fleshy, not jointed, mamma-like legs and a faintly 

 yellowish, chitonized spot on the pleura, for each segment; prothorax 

 with a similarly chitonized area dorsally. 



Abdomen. Prolegs absent; terminating in a prong or horn, circular in 

 cross section, short and arising from a spined, fleshy protuberance of the 

 dorsal anal lobe; anal plate and ventral anal lobe haired; lateral area of 

 dorsal anal lobe haired or bare, ventral anal lobe at posterior-lateral 

 extremities with palpiform appendage appearing 2 jointed. 



KEY TO LARVAE. 



Antennae 4 jointed Adirus trimaculatus (Say) 



Antennae 5 jointed 1 



1. Lateral area of dorsal anal lobe bare 



Janus abbreviatus Say and integer Norton 

 Lateral area of dorsal anal lobe haired 2 



2. Basal joint of antennae faint and incomplete; palpiform appendages of 



ventral anal lobe accompanied by a pair of spines, separate from 

 rest of the ornamentation of lobe; without a pair of yellowish chi- 

 tonized spots on venter of the 9th abdominal segment; anal lobes 



and plate entirely pale Cephus cinctus Norton 



Basal joint antennae complete, distinct, and thick; spines on ventral 

 anal lobe complete, no separation from those approaching palpiform 

 appendages; venter of the !tth abdominal segment with a pair of yel- 

 lowish chitonized spots; anal lobes and plate much yellow chiton 



Harti</iii cressoni iKirby) 



1 S. A. Rohwer, Proc. Ent. Soc. Wash., Vol. XVII, No. 3, 1915, pp. 114- 

 117. 



